Structures and Mechanisms
Mechanical Efficiency
Including:
Gaining Leverage
Let's Sell It!
When Push Comes to Shove
Slow Down
Speed, Distance, Force ... Velocity ... Velocity Ratio
How Efficient Is It?
Linking The Systems
Toying With Efficiency
An Integrated Unit for Grade 8
Written by:
M. Jones, D. Carey, A. Lisowyk, W. Huiterna, C. Quinn (Project
Length of Unit: approximately: 18 hours
September 2001
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Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
The developers are appreciative of the suggestions and comments from teacher colleagues involved
through the internal, external and Theological review.
A sincere thank you to Barry Elliot from Windsor-Essex Catholic District School Board who facilitated the
involvement of the Windsor-Essex, London, Brant/Haldimand-Norfolk, St. Clair and Durham Catholic District
School Boards in the development of elementary Science units.
The following organizations have supported the elementary unit project through team building and
leadership:
The Council of Directors of Ontario
The Ontario Curriculum Centre
The Ministry of Education, Curriculum and Assessment Branch
Catholic Curriculum Cooperative (CCC)
A special thank you to The Institute for Catholic Education who provided leadership, direction and support
through the Advisory and Curriculum Committees.
An Integrated Unit for Grade 8
Written by:
M. Jones, D. Carey, A. Lisowyk, W. Huiterna, C. Quinn (Project Manager)
St. Theresa / Sacred Heart / St. Mark / St. Joseph / Monsignor Feeney Ctr.
(519)663-2088
London Catholic District School Board
[email protected]
Based on a unit by:
M. Jones, D. Carey, A. Lisowyk, W. Huiterna, C. Quinn (Project Manager)
St. Theresa / Sacred Heart / St. Mark / St. Joseph / Monsignor Feeney Ctr.
(519)663-2088
London Catholic District School Board
[email protected]
This unit was written using the Curriculum Unit Planner, 1999-2001, which Planner was developed in the province of
Ontario by the Ministry of Education. The Planner provides electronic templates and resources to develop and share units
to help implement the new Ontario curriculum. This unit reflects the views of the developers of the unit and is not
necessarily those of the Ministry of Education. Permission is given to reproduce this unit for any non-profit educational
purpose. Teachers are encouraged to copy, edit, and adapt this unit for educational purposes. Any reference in this unit
to particular commercial resources, learning materials, equipment, or technology does not reflect any official
endorsements by the Ministry of Education, school boards, or associations that supported the production of this unit.
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Unit Overview
Structures and Mechanisms
Page 1
Mechanical Efficiency An Integrated Unit for Grade 8
Task Context
Catholic Learners are reflective, creative, and holistic thinkers who solve problems and make responsible
decisions with informed moral consciences for the common good. They work effectively as interdependent
team members. Catholic learners are collaborative contributors who find meaning, dignity, and vocation in
work which respects the rights of all and contributes to the common good. They are effective
communicators who speak, write, and listen honestly and sensitively, responding critically in light of gospel
values.
For this grade 8 Science and Technology unit, students will be using problem-solving strategies as they work
in design groups to collaboratively explore each subtask, the successful completion of which leads to a
culminating task. The culminating task requires the cooperative efforts of all group members. Students will
be expected to communicate effectively, in a way that respects the dignity and rights of all members.
Throughout their work, students will be making informed moral choices in light of gospel values, for the
common good of all group members.
Efficiency is an important design consideration in the creation of mechanical systems, from economic, social,
and environmental points of view. In this unit, students will investigate and describe, in qualitative and
quantitative terms, the relationship between force, area, and pressure in relation to liquids and gases. They
will also study simple pneumatic and hydraulic systems, describe the mechanical efficiency of mechanical
systems in qualitative and quantitative terms, design and construct a mechanical toy device that operates
under hydraulic or pneumatic power, and, finally, develop and present a marketing campaign for the product.
It is preferable to have completed the grade 8 "Fluids" unit before beginning this unit, due to its
focus on the properties of fluids and the principles involved in fluid mechanics.
The following questions will be pursued throughout this unit in order for students to develop sufficient
background to create a hydraulically or pneumatically-powered device that operates in an efficient manner:
1. What are the three classes of levers and what are their advantages and disadvantages?
2. What are the factors that need to be considered in the manufacturing and marketing of a product?
3. How are forces transferred in fluids?
4. How does pressure on a liquid versus a gas differ in a closed system?
5. What are some forces that affect the movement of an object?
6. What is velocity ratio and how can it be calculated?
7. What is the mechanical advantage associated with the operation of pulley and lever systems?
8. How can simple hydraulic and pneumatic systems be created, in conjunction with levers, to move objects
as efficiently as possible?
Task Summary
Students will explore and demonstrate an understanding of the factors that contribute to the efficient
operation of mechanisms and systems (e.g., simple machines, Pascal's Law, forces that affect movement,
velocity ratio, hydraulics and pneumatics, consumer needs).
Through the opportunities explored in the subtasks, students will be able to design and make a mechanical
toy device, that will move a given object a specified vertical and horizontal distance, and investigate the
efficiency of the mechanical device.
Students will be given opportunities to explore and demonstrate understanding of the factors that can affect
the manufacturing of a product, including the needs of the consumer. They will then be required to present
their mechanical toy devices in light of their findings.
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Culminating Task Assessment
Students will participate in this culminating task as members of "Smooth Move Toy Company." Students will
be expected to work individually and collaboratively as members of a team. These teams will consist of the
same members who had been working together throughout the subtasks. They will work on designing,
creating, testing (mechanical efficiency and consumer interest), and marketing a toy product. This toy
product must be a mechanical device that is able to move a given object a specified distance through the use
of hydraulic or pneumatic power.
An assessment rubric has been provided which focuses on the students' understanding of concepts, design
skills, communication skills, and the students' ability to relate science and technology to the world outside the
school. The rubric addresses all of the specific criteria set out in the culminating task description and on the
blackline master that will be provided to students.
IT IS VERY IMPORTANT THAT YOU TAKE THE TIME NOW TO READ THROUGH THE COMPLETE
DESCRIPTION OF THE CULMINATING TASK. THIS WILL HELP TO GIVE YOU A CLEAR SENSE OF WHAT
THE SUBTASKS WILL BE LEADING TO AS YOU PROGRESS THROUGH THE UNIT WITH YOUR STUDENTS.
Catholic Graduate Expectations:
CGE 3 - The Catholic Learner is a reflective, creative, and holistic thinker who solves problems and makes
responsible decisions with an informed moral conscience for the common good.
CGE 5f - The Catholic Learner exercises Christian leadership in the achievement of individual and group
goals.
CGE 5g - The Catholic Learner achieves excellence, originality, and integrity in one's own work and supports
these qualities in the work of others.
CGE 2c - The Catholic Learner presents information and ideas clearly and honestly and with sensitivity to
others.
Links to Prior Knowledge
It will certainly work to the students' advantage if they have had the opportunity to complete the Structures
and Mechanisms units from grades 1 to 7 prior to beginning the "Mechanical Efficiency" unit. Grade 8
students should have had the opportunity to complete the "Fluids" unit in the Matter and Materials strand
before beginning this unit.
More specifically, students need to know:
- what the three classes of levers are and how they can be used to reduce the work necessary to move
something
- what friction is and how it can be reduced
- the factors that affect the stability of an object
- how to express and respond to a range of ideas and opinions concisely, clearly, and appropriately
- how to contribute and work constructively in groups
- how to use computer applications such as data collection charts, graphs, and Internet search engines
Considerations
Notes to Teacher
General Notes
1. The culminating activity should be introduced to students, along with the assessment rubric, before
beginning the first subtask. This will serve as part of an introduction to the unit and allow students the
opportunity to "know where they are going" with regard to what they will be prepared to design, construct,
test and market at the end of this unit.
2. This unit does focus on Science and Technology curriculum expectations but it can be linked to other
curriculum areas. Links have been made to the Language, Mathematics, and Visual Arts curricula through a
number of the subtasks and the culminating task. A couple of Visual Arts applications include the promotional
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poster or video presentation to be made as part of the culminating task. Mathematics applications include
recording of data in different formats and analysis of that data, as well as measurement skills. Language
applications include visual and oral communication skills through group work and as part of the culminating
task, as well as writing skills in compiling the results of various investigations.
3. Teachers should ensure that all necessary materials have been located and gathered in advance of
beginning the unit work. These resources include such items as syringes (20 mL) for Subtask 7 and other
for the Culminating Task), tubing, 1 cm square craft wood (e.g., Jinx wood), dowelling, carpenter's glue, hand
saws, tape, plastic 2 L pop bottles, a Newton spring scale, and pulleys. Any video material that is available
through your Board, related to this topic, should be booked in advance of beginning this unit.
Modifications
The activities in this unit are designed to allow for many learning styles and abilities. Teachers will want to
choose small group members carefully to ensure that all students' needs will be met. Individual modifications
to the unit should be considered by the classroom teacher.
Some suggested modifications are:
- recognize effort as well as full task completion
- provide immediate feedback
- clarify expectations at the beginning of each lesson and perhaps provide sample responses for some
students
- repeat important information (concepts and ideas) or allow students to repeat and rephrase
- use pictures and diagrams whenever possible
- encourage students to question for clarification and additional information before beginning work
- vary resources with regard to reading level, amount of visual information use of oral, written, and visual
data
- modify the assignment in terms of: time, quantity of work assigned, nature of the assignment
- stress quality rather than quantity
- provide opportunities for strengths to be used (e.g. artistic abilities could be used to good advantage in
groups)
- team students with varying abilities
- help students keep lesson notes consistent and organized
- adjust reading level of student material or tape-record text
- teach note-taking and organizational skills
- provide research material at their reading level, or with relevant information highlighted
- use reading partners
- assign enrichment tasks
- vary assessment strategies
Special Education Adaptations and Accommodations
1. Provide an encouraging and supportive classroom environment.
2. Refer to individual IEPs and accommodation logs of exceptional learners to make meaningful adaptations
for these students through consultation with the school's special education and ESL teachers.
3. Whenever possible, consult with parents concerning reinforcement of learning expectations and
appropriate working conditions at home.
4. Discuss strategies and objectives with students to ensure that they understand each task, and check
often for comprehension of expectations and activities which will ensure maximizing their potential.
5. Pre-teach vocabulary and key concepts as an introduction to each lesson or segment.
6. Provide students with instructional models which illustrate basic concepts.
7. Provide overviews of lessons which include visual organizations schemes, mapping, or webs.
8. Allow opportunities for practice on less complex tasks before undertaking the key lesson objective.
9. Establish rubrics for a variety of data gathering approaches. These can provide references for evaluation
based on each student's choice of approach.
10. Allow a variety of reporting options and evaluation rubrics for each approach.
11. Encourage heterogeneous grouping of students where at least one student in each group is a strong
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reader.
12. Set up group work to meet the needs of all members. Pair students with physical needs, learning and/or
developmental challenges and explain expectations of those students to group.
13. Consider extension options which provide students with opportunities to reach beyond the curriculum
expectations. This could include expanded research and investigation into related topics and concepts.
Safety
As a matter of good safety practice, please review Ontario Curriculum, Science and Technology document,
pages 8, 9, and 71, reproduced below before beginning this unit. Also, the Science Teachers' Association of
Ontario's document entitled Be Safe! is an excellent safety guide.
In particular, please take careful note of the following, from the Ontario Curriculum, Science and Technology
document:
"It is important that students follow established safety practices in designing, constructing, and experimenting
with structures and mechanisms. These practices include:
- using tools safely to cut, join, and shape objects;
- following proper procedures when comparing mechanical systems and their operation;
- using care when observing and working with objects in motion (e.g., objects that are spinning, swinging,
bouncing, vibrating; gears and pulleys; elevated objects)."
- reprinted from The Ontario Curriculum, Grades 1-8:
Science and Technology, 1998, page 71
"To carry out their responsibilities with regard to safety, it is important not only that teachers have concern
for their own safety and that of their students, but also that they have:
- the knowledge necessary to use the materials, tools, and procedures involved in science and technology
safely;
- the skills needed to perform tasks efficiently and safely.
Students demonstrate that they have the knowledge, skills, and habits of mind required for safe participation
in science and technology activities when they:
- maintain a well-organized and uncluttered work space;
- follow established safety procedures;
- identify possible safety concerns;
- suggest and implement appropriate safety procedures;
- carefully follow the instructions and example of the teacher; and
- consistently show concern for their safety and that of others."
- reprinted from The Ontario Curriculum, Grades 1-8:
Science and Technology, 1998, pages 8-9
Please refer to individual subtasks for specific safety considerations.
Background Information
The Particle Theory
Understanding the particle theory will help students comprehend the dynamics of fluids. The particle theory
consists of five main points:
1. All forms of matter are made up of particles; these particles are so tiny that they cannot be seen with the
naked eye. However, when these small particles move, the movement can be seen.
2. Particles of a pure substance are all identical. Ice, water, and water vapour are all made up of identical
particles, no matter what the state.
3. The attractive forces between particles increase with proximity; this simply indicates that the attractive
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forces (that exist between two particles, which pull the particles towards each other), increase as the
particles move closer towards each other. This also explains why solids are harder than liquids or gases; it
is because the particles are closer together.
4. The spaces between particles are large compared to the size of the particles themselves.
Actually, the spaces are larger than the size of the particles themselves. The spaces are largest in the
gaseous state, which means they can be compressed (e.g., pushing on an inflated balloon) and smallest in
solid state.
5. All particles are in constant motion; this may be a difficult concept for students to conceptualize, especially
when considering something in the solid state, such as wood or steel. However, it is important for students
to know that even though we can not detect movement with the naked eye, the particles within the solid are
moving constantly. The speed of the particles is dependent upon temperature. An increase in temperature
causes an increase in particle movement.
Fluids
Fluids are described as any materials that can flow, namely gases and liquids. Air (gas) and water (liquid)
are two of the most common fluids on our planet. Wind is what we call flowing air. The oceanic tides are an
example of flowing water. The study of fluids can take two forms, static and dynamic. Fluid statics involves
the study of fluids while stationary (at rest) including, for example, how oil works in a car's engine. On the
other hand, dynamic fluids are ones in motion and this area of study includes things such as how an airplane
can remain in the air.
Properties of Fluids
Fluids are very interesting because they have some very unique properties. Three areas are of specific note;
the shape, volume, and mass of fluids. A can of air freshener contains a highly pressurized fluid, once it is
sprayed the fluid vaporizes and spreads throughout the room (due to diffusion from high to low
concentration). Fluids do not have a definite shape and will simply take the shape of whatever they are
poured into. This applies to both liquids and gases. Whether you fill a glass jar with air or water, it will take
the shape of the jar. When considering volume, there is a difference between liquids and gases. Liquids have
a definite volume, which is hard to change, meaning a cup of water will take up the same volume, no matter
what the shape of the container that it is placed in. In this way, liquids are like solids, meaning they are hard
to compress. On the other hand, in the gaseous form, molecules are the farthest apart (refer to Particle
Theory), therefore, they can be compressed considerably. Just think about how heavy your propane tank is
after it has been filled. The reason is because the gas has been forced into the can under high pressure,
therefore the spaces between the particles have been compressed so more particles can be added. Finally,
the mass of a fluid does not change, which intuitively makes sense. If you have a jug of water with a mass
of 1 kg, the mass will not change just because you poured it into a larger jug or one with a different shape.
What Is Force and How Is It Measured?
A force is a push or a pull that causes an object to accelerate or decelerate (i.e., a change in speed and
direction). It can be applied to an object in two ways. It can be applied directly, through the contact of two
objects. For example, when a baseball bat is used to hit a baseball, the bat exerts a force on the ball, causing
it to accelerate in the direction it was hit. The second way force can be applied is indirectly, where the
contact of two objects is not necessary. An example of this type of force is, after a baseball is hit it will rise
to a peak in height and zero velocity, and then will begin to drift back towards the earth, due to the force of
gravity. Whether a force is applied directly or indirectly, it results in the acceleration of an object with a
direction and magnitude.
Using the international system of measurement, force is measured in newtons (N), named after the English
physicist and mathematician Sir Isaac Newton. The students will be doing simplified calculations using
measurement in newtons, which will require them to use a spring scale to measure the force of various
masses. For our purposes we are ignoring acceleration. It is important that students refer to lifting
or raising rather than 'moving' a load. Moving would require them to use calculations of rate of acceleration,
in other words, the force of gravity, with which an object falls to earth. The force needed to hold up a mass
of 100 g using a spring scale is about 1.0 N. One newton (1 N) refers to the amount of force required to
move an object with a mass of 100 g. (against the force of gravity).
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Pressure
Anyone who has had to fix a spare tire, fill an air mattress, or any other pool toy knows a little about
pressure. When we inflate an object such as an air mattress, we are literally placing air molecules inside the
object. If something is underinflated, it is soft and intuitively we know the reason is because there isn't
enough air inside. However, in a more scientific way we could say that there are not enough air molecules
inside the object to maintain the desired pressure. When we add air to an underinflated object, we increase
the number of molecules inside, increasing the forces inside because the air molecules are continually
bumping into one another and the walls of the object (exerting a force on the wall). These molecules are free
to move about inside the object and exert forces against the entire area of the walls. When something is
properly inflated, the air pushes outward with enough force to give the object the shape it needs.
Pressure is defined as the force per unit area of an object. Therefore, the calculation of pressure involves
the force and area over which the force is exerted, so pressure equals force divided by area (P = F/A) and
is expressed in pascals (Pa). When a fluid is acted upon by an external force (pressure), Pascal's law tells
us that the force (pressure) is transmitted uniformly throughout the volume of the fluid.
Pressure in Relation to Volume and Temperature of Fluids
The effect of pressure on fluids was hinted at in the properties of fluids section. Pressure has little effect on
the volume of a liquid (we say it is resistant to compression). In fact, a huge amount of pressure needs to be
applied to even compress a liquid slightly. However, pressure can cause liquids to flow with considerable
force. Just consider the power of the Niagara River, which turns huge turbines and provides power to
Southern Ontario. Gases, on the other hand, are easy to compress (i.e. change the volume), and like liquids
can be quite powerful when pressurized. When a fluid is heated, whether it is a gas or a liquid, the molecules
within the container will begin to move more quickly, increasing the collisions that occur, thereby increasing
the forces within the container and the pressure. Gases are much more reactive to heating than liquids
because the spaces between the molecules expand quite significantly (when compared to the expansion in
liquids). For this reason, all pressurized cans contain a warning against exposure to heat and puncture. If a
pressurized can of gas was heated, the increase in heat and resulting pressure would eventually cause the
can to explode.
In simplest terms, if you heat a liquid and the volume cannot change (because it is in a container), there will
be an increase in pressure. However, if you heat a gas and the volume cannot change, there will be a
drastic increase in pressure.
Velocity, Speed, Motion, and Velocity Ratio
To understand the workings of simple machines, you have to understand some of the fundamentals of
motion, but there isn't a need for a lot of complicated formulas at this point. Motion is described as the change
in location of an object when compared to a specific reference point. The reference point is any stationary
point from which motion can be observed or compared. So, you walking down the street, a ball rolling across
the floor, or a leaf falling from a tree are all examples of motion. Speed is the measure of how quickly an
object is moving and is calculated as the distance covered per unit of time (km/h). Velocity is often confused
with speed but is the speed and direction of a moving object. For example, 60 km/h is the speed of a car,
while 60 km/h north on Niagara St. is a velocity. The velocity ratio represents the "ideal" mechanical
advantage (see below for definition of this term) of a mechanism if friction did not exist. You calculate the
velocity ratio by dividing the distance that the effort force moves by the distance that the load force moves.
Lever
In the glossary a lever is defined as "a simple machine that can lift a weight with less effort." This basic
definition probably hits on the reason levers were invented, to do more work with less effort. Archimedes, a
Greek scientist, lived over 2000 years ago and was the first person to explain how and why levers worked
in mathematical terms. One of his famous quotes "With a big enough lever you can move the world!"
exemplifies the benefits of using a lever. However, levers had been in existence and used long before
Archimedes explained the how and why.
All levers consist of three different parts. These three parts are known as the fulcrum, an effort arm (force
applied here), and a resistance arm (where load or weight rests). The fulcrum is the point or pivot where a
lever moves. The effort arm is where the force is applied to move the resistance arm (load). If the fulcrum is
in the centre of the lever (like in a teeter-totter), then the force applied will be equal to the amount of load you
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can lift.
Consider another example: Imagine you wanted to lift a box that weighed (exerted a force of) 400 N. RA
represents the distance from the fulcrum (F) to the load (R) and is equal to 1 metre. The distance from where
the force is applied (E) and the fulcrum (F) is 10 metres. Then you would only have to apply 40 N of force at
E to lift the load. This is true because of the rule that E x EA = R x RA. Filling in the formula you see that 40 N
times 10 metres = 400 N times 1 metre.
As you can see, the placement of the fulcrum is very important in determining the amount of force needed to
move an object using the lever. In general, there are three different types of levers. A first class lever is one
in which the fulcrum is between the effort and the load (e.g., hammer, car jack). A second class lever is one
in which the fulcrum is at one end of the lever and the load is in the middle (e.g., bottle opener,
wheelbarrow). A third class lever is one in which the fulcrum is at one end of the lever and the load is at the
other end, with the effort in the middle (e.g., fishing pole). Calculating the mechanical advantage of any lever
is simply a matter of dividing the effort arm length by the resistance arm length. Whatever the case, students
should be reminded that it is easier to move a load when it is closer to the fulcrum.
Pulley
The pulley is another simple machine used for lifting heavy things. It consists of a chain or rope wrapped
around a wheel. The pulley is an example of one of the earliest and simplest wheel devices. Scientist believe
the pulley may have been invented in the eighth century B.C.E., in a place that is modern day Syria, where
engineers discovered that a rope placed over a small framed wheel made it easier to lift heavy objects. Since
that time, engineers have used the pulley in many construction projects. The pulley can work in two different
ways. It can change the direction of a force or it can change the amount of force needed to lift an object. The
single pulley does not change the amount of force needed to lift an object, but it does change the direction of
the force. Therefore, there is no mechanical advantage to this system. In this case you can use the weight of
your body to pull the rope down, while the object on the other end of the rope moves up.
However, the pulley is a special form of a lever which CAN reduce the amount of force needed to lift an
object by increasing the distance over which the force is applied. How can this be? The answer is a
moveable pulley or pulley system (more than one pulley), also called a block and tackle (when a fixed pulley
and moveable pulley are used in one system) which is attached to the object you are trying to move.
For example, pretend you are trying to lift a stone weighing 100 kg. This is much too great of a weight for the
average person. Introduce a single fixed pulley and you still have to lift the entire weight, but now the
direction of the force has changed. Instead of lifting the stone straight up, you can use your body weight
(pulling at an angle). Now try a block and tackle system with one fixed pulley and one moveable pulley, and
the force required to lift the stone takes half the effort (50 kg) because there are two ropes supporting the
stone, but the distance you have to lift the stone has doubled (remember, gain in force and loss in distance).
If the weight is still too much, you could add another pulley and decrease the force needed to lift the stone
even further. In these cases the pulley systems result in a mechanical advantage. The mechanical advantage
usually equals the number of rope segments supporting the moveable load, minus the segment on which the
load rests.
In actuality, friction between the rope or chain and the pulleys reduces the mechanical advantage slightly and
tends to limit the total number of pulleys used to a maximum of four.
Mechanical Advantage
In general terms, the mechanical advantage is a measurement of the benefit of using a machine versus not
using a machine and is the amount of times a machine multiplies a force. The mechanical advantage of any
machine can be calculated by dividing the load force (force needed to move an object without use of a
machine) by the effort force (force needed to move an object with a machine).
Mech. Advantage = load force/effort force
For example, if you moved a stone with a 600 N force, using only 200 N of force and a lever, then the
mechanical advantage would be 600/200 = 3. A mechanical advantage of 3 implies that the use of the
machine multiplied the effort force by a factor of 3 or conversely, the person only had to use 1/3 of the force
which would be needed to move the object without a lever.
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Mechanical Efficiency
Mechanical efficiency is a measure of how well a mechanism runs. This calculation helps us determine if the
machine used was worthwhile. More specifically it is calculated as the percent efficiency of a mechanism by
dividing the mechanical advantage you previously calculated by its velocity ratio, and multiplying the result by
100.
Whenever a machine is used, it is subjected to frictional forces (which convert energy to heat), therefore,
the output of a machine is always lower than 100 per cent. In fact, the greater the frictional forces involved,
the less efficient the machine. That's why a pulley system usually is limited to four pulleys, because a number
greater than this usually experiences high frictional forces, negating the benefit of extra pulleys.
- reprinted, in part, from OECTA Teacher Resources Structures and Mechanisms, Grade 8
(Acknowledgements: Northern Region
Catholic Curriculum Cooperative)
Science and Technology References
Glossary of Terms
block and tackle: A combination of fixed and moveable pulleys used for hoisting heavy objects.
compressible: Able to be squeezed into a smaller volume.
displacement: The amount of fluid displaced by an object that is put into the fluid.
efficiency: The comparison of the useful work or energy provided by a machine or system with the actual
work or energy supplied to the machine or system. Efficiency is usually stated as a percentage.
effort: The force supplied to a machine in order to produce an action.
ergonomic: Study of the relationship between work organization and the arrangement, and design of
equipment and how it relates to humans.
first-class lever: A simple machine where the fulcrum is between the effort and the resistance, as a
seesaw.
fluid: Anything that flows; therefore, liquids and gases are fluids.
force: A push or a pull, in order to move something or to stop something from moving.
friction: The resistance that is caused when one object moves against another.
fulcrum: The pivotal or "resting" point of a lever.
hydraulic power: Power that comes from the pressure of a liquid, usually oil. The liquid is forced through
hoses to the area where the force is needed.
hydraulic system: A system that works because of the movement of a liquid or the force of a liquid in a
closed system.
hydraulics: The study of pressure in liquids.
lever: A simple machine upon which an effort is applied to gain force, speed, or distance (e.g., less effort
force needed).
linkage: A system of levers used to transmit motion.
load: The weight of an object that is moved by a machine, or the resistance to movement that a machine has
to overcome.
machine: A device used to make work easier. One of the six basic devices used to do work - inclined plane,
lever, pulley, screw, wedge, and wheel and axle.
mechanical advantage: The gain in force obtained by using a machine. Expresed as
mechanical advantage = load force/effort force
Particle Theory of matter: See Notes to Teacher.
Pascal's Law: An external pressure exerted on a fluid is transmitted uniformly throughout the volume of the
fluid.
pneumatics: The study of pressure in gases.
pressure: The force acting on a certain area of surface (pressure = force/area).
pulley: A simple machine consisting of a grooved wheel over which a rope passes.
resistance: The force to be overcome by a machine.
second-class lever: A simple machine where the resistance is between the effort and the fulcrum, as in
an oar.
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survey: A sampling of information, often compiled by asking people questions or interviewing them.
third-class lever: A simple machine where the effort is between the resistance and the fulcrum, as in a
fishing rod.
velocity: Is the distance traveled per unit time in a given direction.
volume: The amount of space occupied by a substance.
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List of Subtasks
Structures and Mechanisms
Subtask List Page 1
Mechanical Efficiency An Integrated Unit for Grade 8
1
Gaining Leverage
Students will be engaged in a hands-on activity investigating levers. Teacher will direct a lesson to
review the three classes of levers. Students will participate in a hands-on activity using a box of
various levers for review of the classes of levers. They will sort these items according to the three
classes. Students will begin by working in small groups. They then will participate in a large
group-sharing session based on the results of the sorting and classifying work done by each small
group. Students will make a table on the computer to record the classification of the items done in the
large group. An optional follow-up activity can be done by students, individually, with magazine
pictures of a variety of levers that will be part of a collage. These activities will serve as diagnostic
assessment tools for the teacher to ascertain the knowledge and skill levels of the class before
proceeding with the subsequent subtasks.
Catholic Graduate Expectations:
CGE 5 - The Catholic Learner is a collaborative contributor who finds meaning, dignity, and vocation in
work which respects the rights of all and contributes to the common good.
CGE 5a - The Catholic Learner works effectively as an interdependent team member.
CGE 2c - The Catholic Learner presents information and ideas clearly and honestly and with sensitivity
to others.
2
Let's Sell It!
Students will explore, through discussion and research, how consumer expectations and needs, as
well as economic and environmental factors, affect the development and marketing of many consumer
products.
Catholic Graduate Expectations:
CGE 2 - The Catholic Learner is an effective communicator who speaks, writes, and listens honestly
and sensitively, responding critically in light of gospel values.
CGE 2a - The Catholic Learner listens actively and critically to understand and learn in light of gospel
values.
CGE 2b - The Catholic Learner reads, understands, and uses materials effectively.
CGE 2c - The Catholic Learner presents information and ideas clearly and honestly and with sensitivity
to others.
3
When Push Comes to Shove
A) Students will discover the differences in the levels of compressibility between air and water in a
closed system. Students will do this by using two plastic bottles, one which is capped and filled with
air and the other which is capped and filled with water. Both bottles will be squeezed to demonstrate
the differences noted above.
B) Students will investigate the effects of pressure by moving an object using two different sized
syringes. They will move liquid and gas from a smaller syringe to a larger and then reverse the
syringes to go from larger to smaller. They will be investigating the use of pnuematic and hydraulic
systems and the advantages of using a smaller or larger system.
Catholic Graduate Expectations:
CGE 3 - The Catholic Learner is a reflective, creative, and holistic thinker who solves problems and
makes responsible decisions with an informed moral conscience for the common good.
CGE 3c - The Catholic Learner thinks reflectively and creatively to evaluate situations and solve
problems.
CGE 4f - The Catholic Learner applies effective communication, decision-making, problem-solving, and
resource management skills.
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List of Subtasks
Structures and Mechanisms
Subtask List Page 2
Mechanical Efficiency An Integrated Unit for Grade 8
4
Slow Down
Students will investigate and measure the force of friction that affects the movement of an object,
which ultimately has an effect upon the mechanical efficiency of that object. Through
hands-on activities, students will explore the concept of friction. An object will be pulled across a
variety of different textured surfaces and a Newton scale will be used to measure the frictional forces
involved.
Catholic Graduate Expectations:
CGE 3 - The Catholic Learner is a reflective, creative and holistic thinker who solves problems and
makes responsible decisions with an informed moral conscience for the common good.
CGE 3c - The Catholic Learner thinks reflectively and creatively to evaluate situations and solve
problems.
CGE 4f - The Catholic Learner applies effective communication, decision-making, problem-solving, and
resource management skills.
5
Speed, Distance, Force ... Velocity ... Velocity Ratio
Students will come to an understanding of the term "velocity" and then determine the velocity ratio of
various devices. These terms will be defined for students. Students, in groups, will conduct two
experiments to find velocity ratio using levers and pulleys. Blackline master worksheets will be
provided to students, containing a variety of exercises, to help solidify students' understanding of
velocity and velocity ratio.
Catholic Graduate Expectations:
CGE 2 - The Catholic Learner is an effective communicator who speaks, writes, and listens honestly
and sensitively, responding critically in light of gospel values.
CGE 2a - The Catholic Learner listens actively and critically to understand and learn in light of gospel
values.
CGE 2b - The Catholic Learner reads, understands, and uses materials effectively.
6
How Efficient Is It?
Students will determine mechanical advantage and calculate the efficiency of simple mechanical
systems (involving pulleys and levers). Students will investigate this through the use of a simple lever
system and then, students will construct a pulley system. Calculations will be made using these
systems. The work in this subtask will link back to the knowledge gained about velocity ratio in the
previous subtask.
Catholic Graduate Expectations:
CGE 5 - The Catholic Learner is a collaborative contributor who finds meaning, dignity, and vocation in
work which respects the rights of all and contributes to the common good.
CGE 5a - The Catholic Learner works effectively as a interdependent team member.
CGE 2c - The Catholic Learner presents information and ideas clearly and honestly and with sensitivity
to others.
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List of Subtasks
Structures and Mechanisms
Subtask List Page 3
Mechanical Efficiency An Integrated Unit for Grade 8
7
Linking The Systems
Students will construct a lift system, using a set of plans that have been supplied, that incorporates the
use of hydraulics. They will incorporate appropriate levers and ways of linking the components of this
system into their product. Students will then be required to calculate the mechanical efficiency of the
lift system.
Catholic Graduate Expectations:
CGE 3 - The Catholic Learner is a reflective, creative, and holistic thinker who solves problems and
makes responsible decisions with an informed moral conscience for the common good.
CGE 3b - The Catholic Learner creates, adapts, evaluates new ideas in light of the common good.
8
Toying With Efficiency
Students will participate in this culminating task as members of "Smooth Move Toy Company."
Students will be expected to work individually and collaboratively as members of a team. These teams
will consist of the same members who had been working together throughout the subtasks. They will
work on designing, creating, testing (mechanical efficiency and consumer interest), and marketing a
toy product. This toy product must be a mechanical device that is able to move a given object a
specified distance through the use of hydraulic or pneumatic power.
An assessment rubric has been provided which focuses on the students' understanding of concepts,
design skills, communication skills, and the students' ability to relate science and technology to the
world outside the school. The rubric addresses all of the specific criteria set out in the culminating task
description and on the blackline master that will be provided to students.
IT IS VERY IMPORTANT THAT YOU TAKE THE TIME NOW TO READ THROUGH THE COMPLETE
DESCRIPTION OF THE CULMINATING TASK. THIS WILL HELP TO GIVE YOU A CLEAR SENSE OF
WHAT THE SUBTASKS WILL BE LEADING TO AS YOU PROGRESS THROUGH THE UNIT WITH YOUR
STUDENTS.
Catholic Graduate Expectations:
CGE 3 - The Catholic Learner is a reflective, creative, and holistic thinker who solves problems and
makes responsible decisions with an informed moral conscience for the common good.
CGE 5f - The Catholic Learner exercises Christian leadership in the achievement of individual and
group goals.
CGE 5g - The Catholic Learner achieves excellence, originality, and integrity in one's own work and
supports these qualities in the work of others.
CGE 2c - The Catholic Learner presents information and ideas clearly and honestly and with sensitivity
to others.
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Gaining Leverage
Subtask 1
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
80 mins
Description
Students will be engaged in a hands-on activity investigating levers. Teacher will direct a lesson to review the
three classes of levers. Students will participate in a hands-on activity using a box of various levers for review
of the classes of levers. They will sort these items according to the three classes. Students will begin by
working in small groups. They then will participate in a large group-sharing session based on the results of the
sorting and classifying work done by each small group. Students will make a table on the computer to record
the classification of the items done in the large group. An optional follow-up activity can be done by students,
individually, with magazine pictures of a variety of levers that will be part of a collage. These activities will
serve as diagnostic assessment tools for the teacher to ascertain the knowledge and skill levels of the class
before proceeding with the subsequent subtasks.
Catholic Graduate Expectations:
CGE 5 - The Catholic Learner is a collaborative contributor who finds meaning, dignity, and vocation in work
which respects the rights of all and contributes to the common good.
CGE 5a - The Catholic Learner works effectively as an interdependent team member.
CGE 2c - The Catholic Learner presents information and ideas clearly and honestly and with sensitivity to
others.
Expectations
8s101 A
8s87 A
8a26
8s103 A
– use appropriate vocabulary, including correct
science and technology terminology, to
communicate ideas, procedures, and results (e.g.,
use such technical terms as velocity, velocity ratio,
and efficiency);
• demonstrate an understanding of the factors that
contribute to the efficient operation of mechanisms
and systems;
• define the principles of design (emphasis, balance,
rhythm, unity, variety, proportion), and use them in
ways appropriate for this grade when producing and
responding to works of art;
– communicate the procedures and results of
investigations for specific purposes and to specific
audiences, using media works, written notes and
descriptions, charts, graphs, drawings, and oral
presentations (e.g., make a display in which they
compare the ways in which a closed pneumatic
system and a hydraulic system operate the same
size of cylinder);
Groupings
Students Working In Small Groups
Students Working As A Whole Class
Students Working Individually
Teaching / Learning Strategies
Working With Manipulatives
Note-making
Classifying
Brainstorming
Discussion
Assessment
Teacher can use anecdotal record to record
observations of students' abilities to classify
levers appropriately and explain their
mechanical advantage.
Assessment Strategies
Classroom Presentation
Introduction
Questions And Answers (oral)
Observation
Assessment Recording Devices
Rubric
Anecdotal Record
Teaching / Learning
Activity #1 Teacher directed.
1. Review definitions for lever, effort load, load force, and fulcrum.
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Gaining Leverage
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
Subtask 1
80 mins
2. Students work in small groups of four or five to investigate/review how levers work. Provide students
with BLM 1.2 (Gaining Leverage) to lead them through the following activity.
Procedure:
Class 1 Lever (fulcrum in the middle)
i) Place a metre stick with half the length on the desk and the other half extending over the edge. Use the
desk's edge as the fulcrum.
ii) Place a book on the end of the load arm (end that is lying on the desk).
iii) Push down on the effort arm (end extended over the edge), trying this with the fulcrum at two or three
different distances from the load or effort forces.
Class 2 Lever (load in the middle)
i) Tie the book to the middle of the metre stick, so it is attached below the stick.
ii) Put one end of the metre stick on the desk and hold the other end up with book hanging below.
iii) Try to lift the book using the metre stick while it is hanging at a few different places along the stick.
Class 3 Lever (effort in the middle)
i) Tie the book beneath the far end of the metre stick.
ii) While holding the metre stick's end in place on the desk, try to lift the book with the overhanging
extension.
3. Students should be observing the directions of the force associated with the effort and load. (In the class
1 lever, there is a change in direction of force; in the class 2 and 3 levers, there is no change in direction of
force.) Students should observe the advantages or disadvantages of where the fulcrum, load, or effort are.
(The closer the fulcrum is to the load, the easier it is to lift. This will get them thinking and introduce them to
Mechanical Advantage which will be taught in future subtasks.)
4. A note about the three classes of levers is provided for the teacher/students on BLM 1.1 (Notes About
Levers).
Activity #2 Students work in small groups.
1. The teacher will have asked the students to bring in different simple machines that are levers or she/he
will bring in several him/herself. (Any household items: hammer, stapler, can opener, nut cracker, garlic
press, scissors, bottle opener, etc.)
2. Within the small groups of four to five students they discuss the types of levers they have among them
and are asked to catagorize them as they wish.
3. The groups each share their groupings and explain their reasoning to the whole class.
4. The teacher will lead the students, if they have not done this already to catagorize their classifications
into three classes of levers.
5. The teacher records students' input of suggested levers under each heading on overhead BLM 1.3
(Simple Machines - Levers).
6. The students record these into their own notes and then add other examples that they come up with
themselves.
Activity #3 Homework Assignment
1. i) Make a table on the computer to classify the three classes of levers. Under each class, list examples
discussed in class, and add ones (three to five examples) of your own.
ii) On the back of the page, draw and label (fulcrum, load, effort) one of the examples for each class of
levers.
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Gaining Leverage
Subtask 1
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
80 mins
OR
2. On a blank poster-size sheet, have three defined areas for each of the three classes of levers and make
a collage out of pictures cut from magazines or catalogues.
Adaptations
BLM 1.3 can be used as accommodation for ESL, and learners who need help with organization.
Refer to the Notes to Teacher in the Unit Overview for adaptation ideas for students with learning and/or physical
challenges as well as for students identified as ESL.
Resources
Rubric 1 for Gaining Leverage
BLM 1.2 Gaining Leverage
1.2_Gaining Leverage.cwk
BLM 1.3 Simple Machines - Levers
1.3.cwk
BLM 1.1 Notes About Levers
1.1_notes about levers.cwk
household objects (see teacher notes)
hardware catalogues
metre sticks
book (e.g., dictionary)
tape or string to tie book to the metre
stick
Notes to Teacher
1. Examples of levers should be collected by the teacher (and students) as soon as possible. Avoid leaving this
task to the "night before" these levers are needed.
2. You may want to encourage students to begin collecting pictures from magazines and other sources (for their
collage) as part of the introduction to this subtask. They will need some time to collect these resources.
3. Review "Background Information" found in the Overview section, if necessary.
Teacher Reflections
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Let's Sell It!
Subtask 2
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
160 mins
Description
Students will explore, through discussion and research, how consumer expectations and needs, as well as
economic and environmental factors, affect the development and marketing of many consumer products.
Catholic Graduate Expectations:
CGE 2 - The Catholic Learner is an effective communicator who speaks, writes, and listens honestly and
sensitively, responding critically in light of gospel values.
CGE 2a - The Catholic Learner listens actively and critically to understand and learn in light of gospel values.
CGE 2b - The Catholic Learner reads, understands, and uses materials effectively.
CGE 2c - The Catholic Learner presents information and ideas clearly and honestly and with sensitivity to
others.
Expectations
8s110 A
8s111 A
8s113 A
8s114 A
8s115 A
8s116 A
8s102
8s103 A
8s101 A
8s107 A
– identify the kinds of information that assist
consumers in making a decision about buying a
product (e.g., information on performance, durability,
safety, benefits to health);
– identify consumer expectations regarding the
function and effectiveness of a product, using
information collected in a survey they made, and
recognize that expectations may change;
– identify the personal and societal factors that
determine whether a product is used;
– evaluate product manuals or help screens (e.g., a
manual for a video recorder), focusing on clarity,
thoroughness, and general “user-friendliness”, and
identify ways of making the product easier to use;
– assess the impact on the environment of the use
and disposal of various products (e.g., motor oil,
Freon);
– explain the economic, social, and environmental
factors that can determine whether a product is
manufactured (e.g., costs of materials and
equipment, availability of skilled labour, potential
harmfulness of the product);
– compile qualitative and quantitative data gathered
through investigation in order to record and present
results, using diagrams, flow charts, frequency
tables, graphs, and stem-and-leaf plots produced by
hand or with a computer (e.g., produce and analyse
a quotation to complete a job in the home);
– communicate the procedures and results of
investigations for specific purposes and to specific
audiences, using media works, written notes and
descriptions, charts, graphs, drawings, and oral
presentations (e.g., make a display in which they
compare the ways in which a closed pneumatic
system and a hydraulic system operate the same
size of cylinder);
– use appropriate vocabulary, including correct
science and technology terminology, to
communicate ideas, procedures, and results (e.g.,
use such technical terms as velocity, velocity ratio,
and efficiency);
– explain how human weight, height, age, sex, and
Groupings
Students Working As A Whole Class
Students Working Individually
Teaching / Learning Strategies
Research
Discussion
Independent Study
Learning Log/ Journal
Assessment
Assessment Strategies
Questions And Answers (oral)
Essay
Conference
Learning Log
Self Assessment
Assessment Recording Devices
Checklist
Rubric
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Let's Sell It!
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
8s108 A
8e2 A
8e46 A
8a25 A
8a26
8e49 A
8s89 A
Subtask 2
160 mins
physical capability affect the design of products
(e.g., car seats, snowmobiles, zippers);
– analyse the use of symmetry in the ergonomic
design of objects and systems (e.g., office furniture,
computer equipment);
• use writing for various purposes and in a range of
contexts, including school work (e.g., to write
technical instructions, to clarify personal concerns,
to explore social issues, to develop imaginative
abilities);
• provide clear answers to questions and
well-constructed explanations or instructions in
classroom work;
• produce two- and three-dimensional works of art
that communicate a variety of ideas (thoughts,
feelings, experiences) for specific purposes and to
specific audiences, using a variety of art forms;
• define the principles of design (emphasis, balance,
rhythm, unity, variety, proportion), and use them in
ways appropriate for this grade when producing and
responding to works of art;
• express and respond to a range of ideas and
opinions concisely, clearly, and appropriately;
• demonstrate understanding of the factors that can
affect the manufacturing of a product, including the
needs of the consumer.
Teaching / Learning
The focus of this two-part subtask is how consumer expectations and needs, as well as economic and
environmental factors, affect the development and marketing of many consumer products.
Factors students may consider during this subtask include:
i) consumer's physical characteristics (e.g., weight, height, gender, body shape, age, etc.)
ii) buying trends (e.g., fashion, toys, electronics, cell phones, etc.)
iii) product's operational efficiency (e.g., how easy to operate, open, close, move up or down, etc.)
iv) ergonomic design (e.g., comfort, effectiveness in meeting consumer needs, etc.)
v) safety (e.g., sharp edges, weight of materials, electric current, easy-to-follow instructions, etc.)
vi) durability (e.g., standing up to wear and tear, strength of material, etc.)
vii) aesthetics (e.g., shape, appearance, texture, colour, patterns, etc.)
viii) material/product costs (e.g., need to stay within a budget, quality versus quantity, etc.)
ix) environmental issues (e.g., potential health benefits, harmfulness of the product, etc.)
x) moral and ethical issues (e.g., Church teachings regarding development and marketing of certain
products, etc.)
These factors will be investigated within the context of class discussions and an independent research
project.
Activity #1
1. The teacher can introduce this subtask by providing students with the following questions so that they
can individually brainstorm some initial written responses in point form, using their learning logs:
i) When a company begins to design a product what are some of the most important factors that they need to
consider as part of this design process?
ii) When a consumer is thinking about buying products (possibly more expensive items), what are some of
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Let's Sell It!
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
Subtask 2
160 mins
the most important qualities of the products that they might consider before they make their purchases?
Since this is an opportunity to brainstorm ideas, these questions are open-ended. If students need further
guidance or assistance, the teacher could provide some categories such as “personal,” “social,” “economic,”
“environmental,” “product quality,” to encourage some/greater reflection.
2. The teacher can then lead a whole class discussion of students' ideas and categorize student responses
on a chart created on the chalkboard, using some of the categories mentioned above.
3) The teacher could then ask students to reflect on the following:
i) As a Catholic Christian person, reflect on whether or not there are any moral or ethical considerations to
be made when certain products are considered for design, production, marketing, or purchase.
ii) Is what is important to a company in their designs of new products the same as/similar to what is important
to consumers when they are considering the purchase of new products?
Students can discuss answers to these questions as a class, some or all of this information could be
recorded on the chalkboard, and students could then copy the teacher-recorded information into their learning
logs.
4. The teacher should then take about 15 minutes to introduce the new concepts of “aesthetics” and
“ergonomics” orally. When introducing “aesthetics” (i.e., appreciation of the beauty in something), consider
shape, appearance, texture, colour, patterns, and design. “Ergonomics” refers to the study of the mental and
physical capacities of persons in relation to the demands made upon them by various kinds of work. When
considering the ergonomic design of a product, the producer is looking at ways that the product can be
created to operate efficiently, to be comfortable for the consumer, and to be effective in meeting consumer
needs. The teacher could then lead a brief class discussion that focuses on the aesthetic value of certain
pieces of artwork (pre-selected by the teacher), or the ergonomic design of certain chairs (maybe an office
chair that can be found in the school), or computer equipment, in light of the information that the teacher has
just provided for students in introducing these two new concepts (i.e., “aesthetics” and “ergonomics”).
5. In order to give students an opportunity to apply what has been shared/learned so far in this subtask, the
teacher could have students complete one of these two optional activities:
i) The teacher could supply students with different copies of the "Consumer Report." Ask students to select
a consumer product that has been reviewed in one copy of the “Consumer Report” (the version for kids or
the one for adults). Students could record in their learning logs what the strengths and weaknesses of their
selected product are according to the categories under which the product is reviewed. The teacher could
encourage the students to consider some of the categories that were recently discussed in class (e.g.,
economic, social, personal, environmental, aesthetical, ergonomic design, etc.). “Consumer Report”
magazines can be found in local libraries.
ii) Provide students with BLM 2.1 (Comparison Chart) and direct students to complete the chart by comparing
the strengths and weaknesses associated with the production and sales of electric cars versus cars with
combustion engines, under the categories (previously discussed) listed on the chart. This is an activity that
could be completed as a class or independently.
Activity #2
The teacher can then introduce an independent research project to students. Students can select one of the
three topics outlined on BLM 2.2 (Research Assignment) to deal with in their research report. Students could
be given approximately two weeks to complete this assignment. A conference time could be set up for the
teacher to meet with each student after students have had about a week to complete an outline or overview
for their report. This would provide the teacher with the opportunity to ensure that students are “on track”
with regard to meeting the criteria set out for them. The criteria for this outline and for the overall project is
indicated on BLM 2.2 (Research Assignment). Students could also be given an in-class work period during
the first week of the assignment and another in-class work period during the second week of the
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Let's Sell It!
Subtask 2
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
160 mins
assignment. Once again, this would allow the teacher to monitor student progress during the research
reports’ development. BLM 2.3 (Student Checklist) can serve as a self-assessment checklist for students as
they proceed through their project work.
The teacher should review all three research project options with students and be prepared to answer any
questions related to the criteria or timeline which the teacher sets out for them. Review the students
checklist (BLM 2.3 - Student Checklist) and the assessment rubrics (BLM 2a and 2b) together to clarify the
basis for their evaluation.
Adaptations
Refer to the Notes to Teacher in the Unit Overview for adaptation ideas for students with learning and/or physical
challenges as well as for students identified as ESL.
Activity #1, part 5 might serve to provide appropriate options as substitutes for the independent research
assignment. The "Consumer Report" activity or the comparison chart for the two types of cars could be completed
by those students who require significant program adaptations (in place of the independent research project).
Resources
Rubric 2a for Communication
Rubric 2b for Presentation
BLM 2.3 Student Checklist
2.3_rating scale.cwk
BLM 2.2 Research Assignment
2.2_designing a product.cwk
BLM 2.1 Comparison Chart
2.1_comparison.cwk
Commitment: Faith through Service
Catholic Curriculum Cooperative
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Let's Sell It!
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
Subtask 2
160 mins
Notes to Teacher
1. The issue of consumerism as this relates to social justice, and related Church teachings could be further
developed through the Family Life/Religion program.
2. This assignment is being introduced as the second subtask so that students can work on the Activity #2
assignment independently over the course of the completion of the remaining subtasks. This subtask is
designed to address a large number of specific expectations under "Relating Science and Technology to
the World Outside the School" in a way that provides a balance in class discussion/teacher direction and
independent research work.
3. A timeline for Activity #1 and Activity #2 has been suggested throughout the "Teaching/Learning
Strategies" section. The teacher should plan additional time for work periods and presentations. Be sure to
provide additional time, also, to check with students on their progress throughout their independent
research/report writing work.
4. The teacher should introduce the purpose of a learning log to the students (if they have had little
experience with them in the past). The learning log is an ongoing record by the student of what she/he is
doing while working on a particular task or assignment and it makes visible what a student is thinking and/or
doing through frequent recordings over time.
5. Students will need time to present the results of their research assignment. Remember to factor in the
necessary presentation time as you begin this unit. If there is not enough time for a presentation, students
could submit their work for evaluation purposes.
6. A checklist has been provided for student to help them monitor their progress throughout this subtask.
Students can use this checklist for self-assessment purposes. Two assessment rubrics can be used by
the teacher as formative assessment tools. These rubrics address student efforts during the larger group
discussion that precedes the independent research project, and the work done for the research project
itself.
Teacher Reflections
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When Push Comes to Shove
Subtask 3
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
80 mins
Description
A) Students will discover the differences in the levels of compressibility between air and water in a
closed system. Students will do this by using two plastic bottles, one which is capped and filled with air
and the other which is capped and filled with water. Both bottles will be squeezed to demonstrate the
differences noted above.
B) Students will investigate the effects of pressure by moving an object using two different sized
syringes. They will move liquid and gas from a smaller syringe to a larger and then reverse the syringes
to go from larger to smaller. They will be investigating the use of pnuematic and hydraulic systems and
the advantages of using a smaller or larger system.
Catholic Graduate Expectations:
CGE 3 - The Catholic Learner is a reflective, creative, and holistic thinker who solves problems and makes
responsible decisions with an informed moral conscience for the common good.
CGE 3c - The Catholic Learner thinks reflectively and creatively to evaluate situations and solve problems.
CGE 4f - The Catholic Learner applies effective communication, decision-making, problem-solving, and
resource management skills.
Expectations
8s87
8s90 A
8s91
8s93 A
8s101 A
8s103 A
8s102 A
• demonstrate an understanding of the factors that
contribute to the efficient operation of mechanisms
and systems;
– explain how forces are transferred in all directions
in fluids (Pascal’s law);
– describe in quantitative terms the relationship
between force, area, and pressure;
– compare the effect of pressure on a liquid (e.g.,
on water in a syringe) with the effect of pressure on
a gas (e.g., on air in a syringe);
– use appropriate vocabulary, including correct
science and technology terminology, to
communicate ideas, procedures, and results (e.g.,
use such technical terms as velocity, velocity ratio,
and efficiency);
– communicate the procedures and results of
investigations for specific purposes and to specific
audiences, using media works, written notes and
descriptions, charts, graphs, drawings, and oral
presentations (e.g., make a display in which they
compare the ways in which a closed pneumatic
system and a hydraulic system operate the same
size of cylinder);
– compile qualitative and quantitative data gathered
through investigation in order to record and present
results, using diagrams, flow charts, frequency
tables, graphs, and stem-and-leaf plots produced by
hand or with a computer (e.g., produce and analyse
a quotation to complete a job in the home);
Groupings
Students Working In Small Groups
Students Working Individually
Teaching / Learning Strategies
Brainstorming
Discussion
Experimenting
Learning Log/ Journal
Assessment
Students will use the learning log to record
predictions, observations, reflections, and
responses to their conclusions about the
compressibility of a liquid and a gas.
They will also draw diagrams, record
observations, and, through discussion in
their groups, will record in their learning log
the outcomes of their investigation of the
effects of pressure in enclosed systems.
Assessment Strategies
Learning Log
Observation
Questions And Answers (oral)
Self Assessment
Assessment Recording Devices
Rubric
Teaching / Learning
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When Push Comes to Shove
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
Subtask 3
80 mins
Activity #1
Have students work in groups of four or five.
1. Have two plastic bottles prepared, one capped and filled with water and another capped and filled with
air. Have one of each per group. (Caution is advised that students do not squeeze the bottles until they
burst).
2. The teacher leads a discussion of prior knowledge about the particle theory (e.g., attractive forces
between particles are stronger in a liquid than in a gas, therefore, particles are closer together and move less
in a liquid than they do in a gas). Have the students explain what they know about the particles enclosed in
each of the bottles (e.g., both have moving particles, the one with air has more movement and more spaces
between the particles).
3. Have the students predict what they think might happen when the bottles are squeezed (e.g., the bottle
with air is compressible and the bottle with water is not).
4. Have the students squeeze the bottles to observe the results, let them compare their results.
5. Elicit an explanation as to why the bottle with air is squeezable and the one with water is not (e.g., air is
compressible and water is not).
6. Students make an entry in their learning log recording their predictions, observations, and explanation of
the outcome.
Activity #2
Review Hydraulic and Pneumatic Systems (see Notes to Teacher following) with the students.
Safety procedures need to be reinforced: proper usage of syringes (not as weapons), clean up any spills
immediately, and keep work area organized and tidy. Remind/inform students that 1 cm3 =1 mL. Therefore a
20 cm3 syringe = 20 mL.
Students do investigation in small groups of four or five. Distribute copies of BLM 3.1 (Syringe System Setup)
and BLM 3.2 (Syringe System Investigation) to students. This will help them with experiment setup and with
how to complete the experiment. There is also a checklist for students to aid them in completing the entire task
successfully.
1. Experiment setup: (see diagram on BLM 3.1)
i) Clamp a 20 mL syringe to a retort stand.
ii) Using clear plastic tubing connect a 10 mL syringe and tape it to the desk top.
iii) Pull the plunger up fully, filling the syringe with 20 mL of air. Make sure the 10 mL syringe's plunger is
totally pushed in.
iv) To the top of the plunger, add a cardboard square to act as a platform for a 200 g mass.
v) In front of the 10 mL syringe, place an object (e.g., small block). Place the 200 g mass on top of the 20 mL
syringe and observe. (The plunger will be pushed down by the weight, the air pushes the plunger of the 10
mL syringe, which pushes the object along the desk's surface.)
vi) Measure the distance the object was moved.
2. Repeat the same experiment but this time clamp the 10 mL syringe to the retort stand and tape the 20 mL
syringe to the desk top.
3. Have students record their observations in the learning log. They should reflect on the difference
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When Push Comes to Shove
Subtask 3
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
80 mins
observed between the two systems.
4. Repeat the same experiments, this time filling the clamped syringe with water instead of air.
5. The students again record their observations and as a group, draw conclusions and articulate reasoning
to back their conclusions.
6. Calculations could be made to calculate the pressure for each experiment. (Pressure = Force/Area )
One Newton of force is required to lift a 100 g mass. (See Background Notes on "What Is Force and How It
Is Measured?") A 200 g mass is used here, requiring 2 Newtons of force. Students will have to calculate the
area of the small syringe and the area of the large syringe by measuring the radius of the larger opening at
the top of both of the syringes. Recall that, area = pi (3.14) times radius squared. Pressure should be
reported in newtons (N).
Adaptations
Refer to the Notes to Teacher in the Unit Overview for adaptation ideas for students with learning and/or physical
challenges as well as for students identified as ESL.
Resources
Rubric 3 for Syringe System Investigation
BLM 3.2 Syringe System Investigation
3.2.cwk
BLM 3.1 Syringe System Setup
3.1_syringesetup.cwk
2 L plastic pop bottles
water
cardboard squares (4 cm x 4 cm)
tape
retort stands
20 mL syringes
10 mL syringes
clamps
200 g masses
clear plastic tubing
small wooden blocks
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When Push Comes to Shove
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
Subtask 3
80 mins
Notes to Teacher
1. The teacher should become familiar with the following terms: qualitative data (information gathered in
observations in which no measurement takes place) versus quantitative data (data that consists of
numbers and/units of measure, obtained through measurement and through mathematical calculations).
2. A review of the Particle Theory is recommended as part of Activity #1.
3. The teacher needs to review Pascal's Law (Blaise Pascal, a French mathematician who lived 350
years ago, was noted for his intelligence even as a child. He invented the hydraulic press and the syringe.
His law states that an enclosed liquid transmits pressure equally in all directions. When force is applied
from outside, the confined fluid is still distributed evenly in all directions against the inside surface of the
container. The formula for this is Pressure = Force / Area.)
4. Discussion should occur in the form of review about their knowledge of hydraulic and pnuematic
systems. Hydraulic systems use liquid in an enclosed space to transmit force from one place to
another, where pneumatic systems use compressed gas to transmit forces. Remind them that usually
oil is used in hydraulics since it works as a lubricant and non-corrosive. Generally air is used in
pneumatics, since air is in abundance and also does not pollute the atmosphere when it is released. A
hydraulic system works by having an effort force exerted on a smaller area, which then moves through a
system into a bigger area where the force is amplified. Hydraulic systems are used by construction
machinery, car brakes, air planes, etc. Pneumatic systems are used when there needs to be a larger force
and the area in the system is limited, examples would be the dentist drill, large truck brakes, some tools, etc.
5. Review "Background Information" found in the Overview section, if necessary.
Teacher Reflections
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Slow Down
Subtask 4
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
80 mins
Description
Students will investigate and measure the force of friction that affects the movement of an object, which
ultimately has an effect upon the mechanical efficiency of that object. Through hands-on
activities, students will explore the concept of friction. An object will be pulled across a variety of
different textured surfaces and a Newton scale will be used to measure the frictional forces involved.
Catholic Graduate Expectations:
CGE 3 - The Catholic Learner is a reflective, creative and holistic thinker who solves problems and makes
responsible decisions with an informed moral conscience for the common good.
CGE 3c - The Catholic Learner thinks reflectively and creatively to evaluate situations and solve problems.
CGE 4f - The Catholic Learner applies effective communication, decision-making, problem-solving, and
resource management skills.
Expectations
8s95 A
8s99
8s100
8s101 A
8s102 A
8s103 A
– investigate and measure forces that affect the
movement of an object (e.g., friction);
– formulate questions about and identify needs and
problems related to the efficient operation of
mechanical systems, and explore possible answers
and solutions (e.g., test a device at each stage of
its development and evaluate its performance in
relation to specific criteria);
– plan investigations for some of these answers and
solutions, identifying variables that need to be held
constant to ensure a fair test and identifying criteria
for assessing solutions;
– use appropriate vocabulary, including correct
science and technology terminology, to
communicate ideas, procedures, and results (e.g.,
use such technical terms as velocity, velocity ratio,
and efficiency);
– compile qualitative and quantitative data gathered
through investigation in order to record and present
results, using diagrams, flow charts, frequency
tables, graphs, and stem-and-leaf plots produced by
hand or with a computer (e.g., produce and analyse
a quotation to complete a job in the home);
– communicate the procedures and results of
investigations for specific purposes and to specific
audiences, using media works, written notes and
descriptions, charts, graphs, drawings, and oral
presentations (e.g., make a display in which they
compare the ways in which a closed pneumatic
system and a hydraulic system operate the same
size of cylinder);
Groupings
Students Working In Small Groups
Students Working Individually
Students Working As A Whole Class
Teaching / Learning Strategies
Brainstorming
Collaborative/cooperative Learning
Inquiry
Experimenting
Concept Clarification
Assessment
Student contributions during the
brainstorming session are very important as
part of the overall process of new learning.
The greater the details in the student report,
outlining the experiment, the better.
Emphasize to students that they are to
clearly describe every aspect of their
experiments, in detail. Observation, by the
teacher, of each group of students is
necessary to help keep students on task
and so as to easliy address any concerns or
questions as soon as they arise.
Assessment Strategies
Questions And Answers (oral)
Performance Task
Assessment Recording Devices
Rubric
Teaching / Learning
1. Begin by having a class discussion about how friction affects the movement of objects across different
surfaces. Elicit this information from your students. Introduce the term "mechanical efficiency" (see Background
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Slow Down
Subtask 4
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
80 mins
Information section). Ask students to explain the link between mechanical efficiency and friction (e.g., the
mechanical efficiency of a moving object is reduced by frictional forces acting on that object).
2. Conduct a teacher-led brainstorming session, with the whole class, about factors that determine how much
friction there will be between two surfaces that are rubbed together (see Supplementary Teacher Background
Information in Notes to Teacher section). Record this information on the chalkboard.
3. Conduct a second teacher-led brainstorming session about the ways in which friction between two surfaces can
be reduced (see Supplementary Teacher Background Information in Notes to Teacher section). Record this
information on the chalkboard.
4. Students should record the information gathered from their group discussion into their notebooks.
5. Make enough copies of BLM 4.1 (Slow Down) for each student, including the checklist for each student and
the rubric for teacher assessment. Distribute and review each of these handouts together.
6. Have students conduct the investigation outlined on BLM 4.1 (Slow Down).
7. Students use checklist to help them ensure they have covered all necessary parts of the subtask successfully.
8. Provide time for each student to share at least one of the demonstrations that they create in part (d) of BLM
4.1 (Slow Down) with a designated (by the teacher) small group of students.
Adaptations
Refer to the Notes to Teacher in the Unit Overview for adaptation ideas for students with learning and/or physical
challenges as well as for students identified as ESL.
Resources
Rubric 4 for Investigation of Friction
BLM 4.1 Slow Down
4.1_slowdown.cwk
2" x 4" blocks of wood (with hooks)
8.5" x 11" sheets of coarse sandpaper
Newton spring scales
string
lubricants (e.g., oil, grease, or wax)
rollers (e.g., spools)
ball bearings
wheels
bricks (optional)
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Slow Down
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
Subtask 4
80 mins
text books (optional)
500 g masses
Notes to Teacher
Supplementary Teacher Background Information
This information may assist you in facilitating the students in their brainstorming sessions.
Possible factors that determine how much friction there will be between two surfaces that are rubbed
together are:
1. The amount of friction is affected by the nature of the rubbed materials.
2. The force of friction increases when the force pushing the surfaces together increases.
3. The frictional force is almost independent of the size of the area of contact.
Possible ways in which friction can be reduced:
1.
2.
3.
4.
Make the surfaces smoother by sanding and polishing.
Use a lubricant such as oil, grease, wax, or graphite.
Use rollers, ball bearings, or wheels.
Use streamlining, that is, change the shape to reduce air resistance or water resistance.
Teacher Reflections
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Speed, Distance, Force ... Velocity ... Velocity Ratio
Subtask 5
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
120 mins
Description
Students will come to an understanding of the term "velocity" and then determine the velocity ratio of various
devices. These terms will be defined for students. Students, in groups, will conduct two experiments to find
velocity ratio using levers and pulleys. Blackline master worksheets will be provided to students, containing a
variety of exercises, to help solidify students' understanding of velocity and velocity ratio.
Catholic Graduate Expectations:
CGE 2 - The Catholic Learner is an effective communicator who speaks, writes, and listens honestly and
sensitively, responding critically in light of gospel values.
CGE 2a - The Catholic Learner listens actively and critically to understand and learn in light of gospel values.
CGE 2b - The Catholic Learner reads, understands, and uses materials effectively.
Expectations
8s96 A
8s97 A
8s101 A
8s102 A
– distinguish between velocity and speed (i.e.,
define velocity as speed in a given direction);
– determine the velocity ratio of devices with pulleys
and gears (i.e., divide the distance that a load
moves by the distance covered by the force (effort)
required to move it);
– use appropriate vocabulary, including correct
science and technology terminology, to
communicate ideas, procedures, and results (e.g.,
use such technical terms as velocity, velocity ratio,
and efficiency);
– compile qualitative and quantitative data gathered
through investigation in order to record and present
results, using diagrams, flow charts, frequency
tables, graphs, and stem-and-leaf plots produced by
hand or with a computer (e.g., produce and analyse
a quotation to complete a job in the home);
Groupings
Students Working As A Whole Class
Students Working In Small Groups
Teaching / Learning Strategies
Experimenting
Problem-solving Strategies
Assessment
Assessment Strategies
Performance Task
Questions And Answers (oral)
Assessment Recording Devices
Rubric
Teaching / Learning
1. Distribute a copy of BLM 5.1 (Velocity) and BLM 5.2 (Velocity Ratio) to each student.
2. Use these sheets as your vehicles for teaching the concepts of velocity and velocity ratio.
3. Have the students complete the work contained on the sheets as you guide students through them.
4. Make sure students understand the concepts involved before having them conduct the investigations which
follow. Answers for these blackline masters can be found on BLM 6.8 (Answer Sheet).
5. Group the students based on the availability of materials in your school. Groups of five or six students are
suggested.
6. Distribute a copy of BLM 5.3 (Velocity Ratio Using Levers) to each student.
7. Have each group of students set up their materials by following the procedure indicated on the blackline
master.
8. Direct the students to conduct the investigation and complete the written work on BLM 5.3 (Velocity Ratio Using
Levers).
9. Discuss the results of their investigation as a class. Make sure the students are able to calculate velocity ratio
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Speed, Distance, Force ... Velocity ... Velocity Ratio
Subtask 5
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
120 mins
using the data recorded on their observation charts and the formula that is indicated on the blackline master.
10. Distribute a copy of BLM 5.4 (Velocity Ratio Using Pulleys) to each student.
11. Have the groups conduct the investigation of velocity ratio with pulleys, using the materials listed and the
instructions provided on BLM 5.4 (Velocity Ratio Using Pulleys).
12. Using the results of their investigation, the students then complete the remainder of BLM 5.4 (Velocity Ratio
Using Pulleys).
13. Review the worksheet together to make sure that the students understand the relationship between how far
the effort force moves and how far the load force moves. Answers to the questions found in the "Conclusions"
section can be found on BLM 6.8 (Answer Sheet).
14. If you feel that additional practice of calculations is required, for any of the students in your class, refer to any
of the appropriate Ministry of Education approved Science and Technology textbooks for work samples and
examples.
Adaptations
Refer to the Notes to Teacher in the Unit Overview for adaptation ideas for students with learning and/or physical
challenges as well as for students identified as ESL. Please see BLM 5.5 (Observations Table).
Resources
Rubric 5 for Velocity Ratio Investigations
BLM 5.4 Velocity Ratio Using Pulleys
5.4_PulleysVR.cwk
BLM 5.5 Observations Table
5.5_observtable.cwk
BLM 5.1 Velocity
5.1_Velocity.cwk
BLM 5.2 Velocity Ratio
5.2_velocity ratio.cwk
BLM 5.3 Velocity Ratio Using Levers
5.3_Levers VR.cwk
1 cm square craft wood (60 cm in length)
pulleys (single)
heavy string
4" x 1/4" bolts and nuts
tape
metre sticks
500 g masses
retort stands
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Speed, Distance, Force ... Velocity ... Velocity Ratio
Subtask 5
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
120 mins
rulers (cm)
student desks
ring clamps
Notes to Teacher
1. A machine is a device used to apply or transmit mechanical power. Its function may be to overcome
resistance to motion or to change shape or size at one end of an object by applying a force, often at some other
point. The multiplication of forces is possible in mechanical devices, enabling work to be performed that human
strength could not manage alone. The efficiency and the advantage gained from the use of any machine can
be quantified by calculating simple ratios (as outlined in subtasks 5 and 6).
2. The focus for this subtask is “velocity” and “velocity ratio.” Velocity can be considered to be speed in a given
direction. Velocity ratio is the ratio of the distance the effort force moves to the distance the load force moves.
Students need to have a clear understanding of these concepts before beginning the investigations and to help
with their understanding of “efficiency” in subtask 6.
3. Your students are asked to create a table, for recording their observations, on BLM 5.3 (Velocity Ratio Using
Levers). A sample copy of this table is found on BLM 5.5 (Observations Table). This table could be reproduced
for students with special learning needs who may experience great difficulty in trying to produce this table
independently.
4. Be sure to caution your students to handle the 500 g masses with care so as not to drop them. Instruct
students to use safety glasses throughout the investigation.
5. Answers for the worksheet are found on BLM 6.8 (Answer Sheet).
6. Students’ work for this subtask can be assessed using the rubric provided.
Teacher Reflections
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How Efficient Is It?
Subtask 6
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
120 mins
Description
Students will determine mechanical advantage and calculate the efficiency of simple mechanical systems
(involving pulleys and levers). Students will investigate this through the use of a simple lever system and then,
students will construct a pulley system. Calculations will be made using these systems. The work in this
subtask will link back to the knowledge gained about velocity ratio in the previous subtask.
Catholic Graduate Expectations:
CGE 5 - The Catholic Learner is a collaborative contributor who finds meaning, dignity, and vocation in work
which respects the rights of all and contributes to the common good.
CGE 5a - The Catholic Learner works effectively as a interdependent team member.
CGE 2c - The Catholic Learner presents information and ideas clearly and honestly and with sensitivity to
others.
Expectations
8s98 A
8s101 A
8s102 A
– predict the mechanical efficiency of using different
mechanical systems (e.g., a winch).
– use appropriate vocabulary, including correct
science and technology terminology, to
communicate ideas, procedures, and results (e.g.,
use such technical terms as velocity, velocity ratio,
and efficiency);
– compile qualitative and quantitative data gathered
through investigation in order to record and present
results, using diagrams, flow charts, frequency
tables, graphs, and stem-and-leaf plots produced by
hand or with a computer (e.g., produce and analyse
a quotation to complete a job in the home);
Groupings
Students Working As A Whole Class
Students Working In Small Groups
Teaching / Learning Strategies
Experimenting
Problem-solving Strategies
Assessment
Assessment Strategies
Performance Task
Questions And Answers (oral)
Assessment Recording Devices
Rubric
Teaching / Learning
1. Keep the student groups the same as for subtask 5.
2. Distribute copies of BLM 6.1 (Mechanical Advantage - Levers).
3. Instruct the students to set up their apparatus similar to the way they did for the velocity ratio experiment using
the levers.
4. Have the groups complete BLM 6.1 (Mechanical Advantage - Levers) by following the instructions on the sheet.
5. Review what has been previously discovered about mechanical advantage before proceeding to the
investigation of mechanical advantage with pulleys.
6. Distribute a copy of BLM 6.2 (Mechanical Advantage - Pulleys).
7. Instruct the students to set up their apparatus similar to the way they did for the velocity ratio experiment using
pulleys.
8. Have students follow the instructions given on BLM 6.2 (Mechanical Advantage - Pulleys) and complete their
investigation of mechanical advantage using pulleys.
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How Efficient Is It?
Subtask 6
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
120 mins
9. Distribute a copy of BLM 6.3 (VR/MA with Levers) to each student.
10. Work your way through this blackline master with the whole class, having the students complete the worksheet
together.
11. Refer to BLM 6.8 (Answer Sheet) for the correct answers and have students check their work as you supply
the correct answers, once students' original answers have been completed.
12. Distribute a copy of BLM 6.4 (Summary Sheet (MA/VR)) to each student. Allow them to complete it. Make
sure that students have a good understanding of the relationship between mechanical advantage and velocity
ratio.
13. Introduce the term "efficiency" to the students. As a group, come up with a definition for "efficiency."
14. Distribute a copy of BLM 6.5 (Efficiency) to each student.
15. Discuss the formula for finding percentage efficiency and complete the problem at the top of the page.
16. Allow the students to answer the remaining questions for BLM 6.5 (Efficiency) in the spaces provided.
17. There is space at the bottom of the page for students to write a definition of efficiency.
18. If you feel that additional practice in calculating mechanical advantage and/or percentage efficiency is
required, for any of the students in your class, refer to any of the appropriate Ministry of Education approved
Science and Technology textbooks for work samples and examples.
19. Answers for BLM 6.4 (Summary Sheet (MA/VR)) and 6.5 (Efficiency) are found on BLM 6.8 (Answer Sheet).
Adaptations
Refer to the Notes to Teacher in the Unit Overview for adaptation ideas for students with learning and/or physical
challenges as well as for students identified as ESL. Please see BLM 6.6 (Observations Tables).
Resources
Rubric 6 for MA/ME Investigations
BLM 6.1 Mechanical Advantage - Levers
6.1_MALevers.cwk
BLM 6.2 Mechanical Advantage - Pulleys
6.2_MAPulleys.cwk
BLM 6.3 VR/MA with Levers
6.3_VRMALevers.cwk
BLM 6.4 Summary Sheet (MA/VR)
6.4_SummarySheet.cwk
BLM 6.5 Efficiency
6.5_Efficiency.cwk
BLM 6.6 Observations Tables
6.6_observtable.cwk
BLM 6.7 Multiple-Choice Test
6.7_MCTest.cwk
BLM 6.8 Answer Sheet
6.8_Answers.cwk
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How Efficient Is It?
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
Subtask 6
120 mins
4" x 1/4" bolts and nuts
1 cm square craft wood (60 cm lengths)
heavy string
retort stand
ring clamp
ruler (cm)
Newton spring scale
500 g masses
student desks
metre sticks
Notes to Teacher
1. The focus of this subtask is “mechanical advantage” and “mechanical efficiency.”
2. Mechanical advantage is a number that tells how many times a machine multiplies the effort force.
Mechanical advantage is calculated by dividing the load force by the effort force. Be sure that the students
have a clear understanding of mechanical advantage before beginning the investigations. Also help with their
understanding of “efficiency” (to be looked at later in this subtask).
3. Your students are asked to create a table, for recording their observations on BLMs 6.1 (Mechanical
Advantage - Levers) and 6.2 (Mechanical Advantage - Pulleys). Sample copies of these tables are found on
BLM 6.6 (Observations Tables). This table could be reproduced for students with special learning needs who
may experience great difficulty in trying to produce this table independently. Be sure to caution your students to
handle the 500 g masses with care so as not to drop them. Instruct students to use safety glasses throughout
the investigation.
4. Mechanical efficiency looks at the relationship between mechanical advantage and velocity ratio. The result
is expressed as a percent. To calculate mechanical efficiency, divide the mechanical advantage by the velocity
ratio and then multiply the result (quotient) by 100. No machine is 100% efficient. Factors such as friction and
gravity reduce the efficiency of machines.
5. Answers for the worksheet are found on BLM 6.8 (Answer Sheet).
6. Students’ work for this subtask can be assessed using the rubric provided.
7. A multiple-choice test can be found as part of the blackline masters for this subtask (BLM 6.7). It is
suggested that this test be used as a summative assessment tool at the end of the unit (after completion of the
culminating task). Students should be advised to review their learning log entries (from previous subtasks) and
the worksheets associated with subtasks 5 and 6 in preparation for this test. Give students notice as soon as
possible that there will be a test at the end of this unit so that they have time to prepare themselves to write it.
Teacher Reflections
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Linking The Systems
Subtask 7
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
160 mins
Description
Students will construct a lift system, using a set of plans that have been supplied, that incorporates the use of
hydraulics. They will incorporate appropriate levers and ways of linking the components of this system into
their product. Students will then be required to calculate the mechanical efficiency of the lift system.
Catholic Graduate Expectations:
CGE 3 - The Catholic Learner is a reflective, creative, and holistic thinker who solves problems and makes
responsible decisions with an informed moral conscience for the common good.
CGE 3b - The Catholic Learner creates, adapts, evaluates new ideas in light of the common good.
Expectations
8s94
8s101 A
8s99
8s98 A
8e46
8e47
8m35 A
8m36
8m91
8m93
8s104
8s105
8s102 A
– explain, using their observations, how the use of
appropriate levers and ways of linking the
components of fluid systems can improve the
performance of the systems (e.g., systems in a
steam shovel, in a robot);
– use appropriate vocabulary, including correct
science and technology terminology, to
communicate ideas, procedures, and results (e.g.,
use such technical terms as velocity, velocity ratio,
and efficiency);
– formulate questions about and identify needs and
problems related to the efficient operation of
mechanical systems, and explore possible answers
and solutions (e.g., test a device at each stage of
its development and evaluate its performance in
relation to specific criteria);
– predict the mechanical efficiency of using different
mechanical systems (e.g., a winch).
• provide clear answers to questions and
well-constructed explanations or instructions in
classroom work;
• listen attentively to organize and classify
information and to clarify thinking;
• demonstrate a verbal and written understanding of
and ability to apply accurate measurement and
estimation strategies that relate to their
environment;
• identify relationships between and among
measurement concepts (linear, square, cubic,
temporal, monetary);
• systematically collect, organize, and analyse
primary data;
• interpret displays of data and present the
information using mathematical terms;
– design and make a mechanical system that is
operated by hydraulic or pneumatic power;
– select and use appropriate materials and
strategies to make a product;
– compile qualitative and quantitative data gathered
through investigation in order to record and present
results, using diagrams, flow charts, frequency
tables, graphs, and stem-and-leaf plots produced by
hand or with a computer (e.g., produce and analyse
a quotation to complete a job in the home);
Groupings
Students Working Individually
Students Working In Small Groups
Teaching / Learning Strategies
Collaborative/cooperative Learning
Fair Test
Model Making
Problem-solving Strategies
Assessment
Assessment Strategies
Performance Task
Questions And Answers (oral)
Learning Log
Assessment Recording Devices
Anecdotal Record
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Linking The Systems
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
Subtask 7
160 mins
Teaching / Learning
Students should be provided with BLMs 7.1 to 7.9. These “Tips,” “Assembly Instructions,” and schematic drawings
provide students with clear directions for constructing a “Hydraulic Test Lever”. BLM 7.9 (Instructions for Lever
Test) provides students with instructions for testing their device.
Give students time to review the instructions, allowing them to do this independently. Once they have reviewed all
of the instructions and schematic drawings, ask each student to write out answers to the following questions in
their learning logs:
a) Does this “Hydraulic Test Lever” appear to be of solid, stable construction? What part(s) of the system provide
stability and strength? (E.g., the length of the base frame, cross braces)
b) What purpose does the pivot assembly serve? Could this device operate just as effectively without the pivot
assembly? (E.g., the syringe is not just moving straight up and down, but through a slightly curved path as well. If
the syringe is unable to pivot, the plunger would only extend a short distance before siezing.)
c) What are the advantages of using a lever as part of this device? (E.g., reduces the effort needed to move an
object, increases mechanical advantage of the device.)
d) What are the advantages of using a hydraulic assembly as part of this device? (E.g., the forces transmitted are
multiplied, an effort force exerted on a small area is transmitted through the system onto a large area where the
force is magnified, a large ratio of large piston (supporting piston) to small piston (pushing piston) will multiply the
force considerably.)
Accuracy in construction is very important to the overall operation of this device. Instructions should be followed
very carefully by students.
Once students have completed the construction of their lift system, have them discuss their answers to the two
questions that they wrote answers for related to stability and the pivot assembly. Have them make any necessary
additions or changes to their answers (using a different colour ink or marker than was used for their original
answers). The teacher then needs to evaluate students' original responses and the additions/changes that
students made to their original answers (which indicate the learning that has taken place over the course of the
construction work).
Students must then calculate mechanical advantage and calculate the efficiency of the mechanical device.
Students should attach a load force of about 200 g to the load end of the boom. They can then test the lift
system five times, moving the adjustment pin into a different lever advantage adjustment hole each time (thus
changing the location of the effort force on the lever, in relation to the fulcrum, each time). Results could be
recorded on a graph of their choice. It can then be determined as to which lever position provides the
greatest/least mechanical efficiency. Students can then add a statement to their learning logs that reflects their
understanding of how the lever position affects mechanical efficiency.
Refer to “Background Information” under “Lever,” Mechanical Advantage,” and "Mechanical Efficiency” sections:
1. Velocity Ratio = (distance moved by effort force) / (distance moved by load force)
2. Recall the rule that E x EA = R x RA (“E” is effort force, “EA” is distance from where effort force is applied to
fulcrum, “R” is load force, and “RA” is distance from load force to fulcrum). Since we know what “R” is (200 g), and
we can find “EA” and “RA” by measuring these distances, “E” can then be calculated.
3. Mechanical Advantage can then be calculated: load force / effort force (load force = output force and effort
force = input force).
4. Mechanical Efficiency = (mechanical advantage / velocity ratio) x 100, and can be calculated using the data
gathered from calculations in steps 1, 2, and 3 above.
The teachers can pool the results of their tests with those of their peers to check for consistency and the level of
accuracy of calculations. The teacher may also want to run these same tests in order to come up with an accurate
set of answers to be used for comparison purposes with the students' results. The results of their work related to
students' calculations becomes the final part of the assessment associated with this subtask.
Adaptations
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Linking The Systems
Subtask 7
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
160 mins
Refer to the Notes to Teacher in the Unit Overview for adaptation ideas for students with learning and/or physical
challenges as well as for students identified as ESL.
Students who experience difficulty with fine motor control or who might find it difficult to follow the detailed
schematic drawings might be paired with another student in the class who can more easily manage this activity. If
this is not possible, the teacher may have to provide more one-on-one guidance and support for these students.
Resources
Rubric 7 for Hydraulic Test Lever Activity
BLM 7.1 Hydraulic Test Lever - Tips
tips.pdf
BLM 7.2 Assembly Instructions
7.2_assembly1.pdf
BLM 8_ Assembly Instructions
8_assembly2.pdf
BLM 7.4 Base Frame Design
7.4_base frame.cwk
BLM 7.5 Tower Frame Design
7.5_tower frame.cwk
BLM 7.6 Boom Frame Design
7.6_boom frame.cwk
BLM 7.7 Syringe Assembly
7.7_syringe assembly.cwk
BLM 7.8 Side View / Complete Assembly 7.8_Side View All.cwk
BLM 7.9 Instructions for Lever Test
7.9_testing steps.pdf
1 cm square craft wood (Jinx wood)
syringes 10 mL and 20 mL
3/16" doweling
electrical tape
Carpenter's glue or glue guns
hand-powered drills with 13/64" or 7/32"
bits
cardboard gussets
steel or plastic squares
mitre boxes
hand saws
cm rulers
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Linking The Systems
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
Subtask 7
160 mins
200 g masses
Notes to Teacher
1. The purpose of the question, "Does this 'Hydraulic Test Lever' appear to be of solid, stable construction?" is
to check students' background knowledge related to "Stability" (grade 3) and "Structural Strength and Stability"
(grade 7). Students should understand the value of cross bracing and the strength associated with
triangulation. They also need to understand the value of increasing the length of the base, which would create
greater stability for the mechanical device if a heavier load was introduced.
2. Review students' written answers and additions/corrections to the initial two questions related to stabiltiy and
the pivot assembly. Students need to understand that stability and the pivot assembly are important to the
successful assembly of this mechanical device.
3. Since the performance task does not cover the full design process (e.g., the planning of your design has
been provided for you), as part of your assessment you need to focus on whether or not they can successfully
make this mechanical device, how well they explain the advantage of the lever and its various positions as part
of this device, how well they can explain the advantages of using a hydraulic system to operate this device,
whether or not their test results for mechanical efficiency reflect a clear understanding of this concept, and
students' accuracy in recording the results of their tests (via their graphs).
4. The 200 g mass that is to be attached to the end of the boom, could be attached with something as simple
as tape. No "basket-type" attachment is necessary.
5. Review "Background Information" found in the Overview section, if necessary.
Teacher Reflections
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Toying With Efficiency
Subtask 8
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
280 mins
Description
Students will participate in this culminating task as members of "Smooth Move Toy Company." Students
will be expected to work individually and collaboratively as members of a team. These teams will consist
of the same members who had been working together throughout the subtasks. They will work on
designing, creating, testing (mechanical efficiency and consumer interest), and marketing a toy product.
This toy product must be a mechanical device that is able to move a given object a specified distance
through the use of hydraulic or pneumatic power.
An assessment rubric has been provided which focuses on the students' understanding of concepts,
design skills, communication skills, and the students' ability to relate science and technology to the world
outside the school. The rubric addresses all of the specific criteria set out in the culminating task
description and on the blackline master that will be provided to students.
IT IS VERY IMPORTANT THAT YOU TAKE THE TIME NOW TO READ THROUGH THE COMPLETE
DESCRIPTION OF THE CULMINATING TASK. THIS WILL HELP TO GIVE YOU A CLEAR SENSE OF
WHAT THE SUBTASKS WILL BE LEADING TO AS YOU PROGRESS THROUGH THE UNIT WITH YOUR
STUDENTS.
Catholic Graduate Expectations:
CGE 3 - The Catholic Learner is a reflective, creative, and holistic thinker who solves problems and makes
responsible decisions with an informed moral conscience for the common good.
CGE 5f - The Catholic Learner exercises Christian leadership in the achievement of individual and group
goals.
CGE 5g - The Catholic Learner achieves excellence, originality, and integrity in one's own work and
supports these qualities in the work of others.
CGE 2c - The Catholic Learner presents information and ideas clearly and honestly and with sensitivity to
others.
Expectations
8s94
8s98
8s101
8s103
8s104 A
8s105 A
– explain, using their observations, how the use of
appropriate levers and ways of linking the
components of fluid systems can improve the
performance of the systems (e.g., systems in a
steam shovel, in a robot);
– predict the mechanical efficiency of using different
mechanical systems (e.g., a winch).
– use appropriate vocabulary, including correct
science and technology terminology, to
communicate ideas, procedures, and results (e.g.,
use such technical terms as velocity, velocity ratio,
and efficiency);
– communicate the procedures and results of
investigations for specific purposes and to specific
audiences, using media works, written notes and
descriptions, charts, graphs, drawings, and oral
presentations (e.g., make a display in which they
compare the ways in which a closed pneumatic
system and a hydraulic system operate the same
size of cylinder);
– design and make a mechanical system that is
operated by hydraulic or pneumatic power;
– select and use appropriate materials and
strategies to make a product;
Groupings
Students Working Individually
Students Working In Small Groups
Teaching / Learning Strategies
Case Study
Collaborative/cooperative Learning
Fair Test
Model Making
Problem-solving Strategies
Assessment
1. The design rubric (with the four
categories indicated) that has been provided
for the overall assessment of students' work
is given in this subtask.
2. The need for observation (on the part of
the teacher) during students' work is
essential in determining students' individual
contributions to group's construction work.
3. A brief conference with each student, as
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Toying With Efficiency
Subtask 8
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
8s106 A
8s118 A
8s117
8e1
8e46
8e47
8e49
8m35
8m36
8m77
8m91
8m94
8s87
8s88
8s89
8s112
8s111
– produce technical drawings and layout diagrams
of a structure or a mechanical system that they are
designing, using a variety of resources.
– evaluate their own designs against the original
need, and propose modifications to improve the
quality of the products.
– make informed judgements about products
designed and made by others;
• communicate ideas and information for a variety of
purposes (to evaluate information, to compare
points of view) and to specific audiences, using
forms appropriate for their purpose (e.g., a survey
soliciting opinions on an environmental issue) and
features appropriate to the form (e.g., focused
questions);
• provide clear answers to questions and
well-constructed explanations or instructions in
classroom work;
• listen attentively to organize and classify
information and to clarify thinking;
• express and respond to a range of ideas and
opinions concisely, clearly, and appropriately;
• demonstrate a verbal and written understanding of
and ability to apply accurate measurement and
estimation strategies that relate to their
environment;
• identify relationships between and among
measurement concepts (linear, square, cubic,
temporal, monetary);
• identify, create, and solve simple algebraic
equations;
• systematically collect, organize, and analyse
primary data;
• evaluate data and draw conclusions from the
analysis of data;
• demonstrate an understanding of the factors that
contribute to the efficient operation of mechanisms
and systems;
• design and make systems of structures and
mechanisms, and investigate the efficiency of the
mechanical devices within them;
• demonstrate understanding of the factors that can
affect the manufacturing of a product, including the
needs of the consumer.
– recognize the importance of unbiased testing of
control samples and independent evaluation of the
test results before a product is manufactured;
– identify consumer expectations regarding the
function and effectiveness of a product, using
information collected in a survey they made, and
recognize that expectations may change;
280 mins
she/he is preparing her/his design, would
provide the teacher with some insight into
how effectively each student is using the
background knowledge and experience
gained from subtasks 1 to 7.
4. Reviewing students' answers to the
questions outlined on BLM 8.3 (page 2), as
part of the conference or independent of the
conference, will also help the teacher to
evaluate each student's individual
contributions to this task and her/his
understanding of efficiency, "selling
features," suggested improvements, and
real world applications of hydraulic and
pneumatic power.
5. An anecdotal record of the results of
each of these conferences could be
completed.
Assessment Strategies
Classroom Presentation
Conference
Performance Task
Learning Log
Assessment Recording Devices
Anecdotal Record
Rubric
Teaching / Learning
1. Students are presented with the case study outlined on BLM 8.3 (Case Study Outline). Please read,
duplicate, and distribute this to students. Time should be taken to carefully review the entire outline together.
Review, with students, the rubric being used for the evaluation of students' work for this culminating activity.
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Toying With Efficiency
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
Subtask 8
280 mins
2. Set up the timeline dates with students so that they can record them on their copy of BLM 8.3 (Case Study
Outline). Students will then have a better idea of how to budget their time most effectively.
3. Safety Considerations:
Please refer to safety procedures outlined in the Overview section. Give specific consideration to the safe
use of saws, careful use of any hot glue (with cold water available to soothe burns on hands), the need for
safety goggles to be worn during construction (e.g., sawing, drilling, and sanding), the pressure that can
build up in syringes when they are compressed, and the need for students to stand clear of the moving boom
arms on the mechanical device.
Adaptations
1. Refer to the Notes to Teacher in the Unit Overview for adaptation ideas for students with learning and/or
physical challenges as well as for students identified as ESL.
2. Students who have special needs may need to verbally articulate a design proposal to you. The two
BLMs (8.1 "Shovel Arm Assembly" and 8.2 "Boom Extension Design") could be supplied to students with
special needs who might not be able to create technical drawings on their own. These students could then
be guided through the rest of the process by her/his team members.
3. There are several alternative tasks that could be incorporated into this culminating activity for those
students in need of an additional challenge:
a) The president has indicated that budget guidelines will be provided so that this team's members will be
aware of spending limits in preparing a prototype of this new toy. A store needs to be set up with a wide
variety of the materials that are listed in the "Resources" section of this subtask. Each of these items needs
to have a price attached to it. Some prices have been suggested for your convenience next to each of the
materials listed in the "Resources" section. Students then need to be given about $25 of "Smooth Move"
money which can be spent on items they need to construct their mechanical devices. Remind students that
they cannot exceed their budgeted amount of money, so they must really plan ahead before construction
begins. Students should be given an opportunity to visit the store in advance of their planning work so that
they have some idea of the materials that are available to them.
The team must then decide, by way of consensus, what materials (and respective quantities) need to be
purchased for construction purposes. Unused materials cannot be returned to the store for refunds. An
accurate review/assessment of their plans are critical at this stage. If students are not purchasing materials
(since this is optional), they must be able to demonstrate their reasoning related to the quantity and type of
materials they require to construct their model. The idea of using an economical approach to obtaining
building materials is essential.
All necessary tools need to be made available to students at no "cost." These tools are denoted by the
picture of the test tube in the "Resources" section. All materials denoted by the picture of a tube of liquid
must be purchased from the store at the given prices.
b) The level of mechanical efficiency of the finished product could be calculated, with students using the
background knowledge they have acquired through previous subtasks.
c) Making use of all knowledge gained from the "Let's Sell It!" subtask 2, the toy must be as marketable as
possible. Teams must present their mechanical toys to potential "consumers" (student peers and/or parents)
using an effective marketing strategy, with the responsibilities for the presentation shared equally by all group
members. Posters, video material, and/or the development of a commercial for their product could be
completed.
A survey and an unbiased test should be designed by each student group that identify consumer
expectations regarding the function and effectiveness of their mechanical device. When creating the survey
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Toying With Efficiency
Subtask 8
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
280 mins
and the test, students should consider:
- information that assists consumers in making a decision about whether or not to purchase and/or use a
product (e.g., performance, durability, uniqueness, appeal, safety)
- a field test with consideration given to who will be part of the sample and what the sample size will be, as
well as an independent evaluation of the test results before the product would actually be mass produced
and sold
For students' surveys and product tests, some careful consideration should be given to who will constitute
the sample groups of people needed for this task. Allow the students to suggest who could make up the
sample groups. The teacher might want to consider pre-arranging access to students and/or teachers in
other classes throughout the school to serve as possible sample groups for students' surveys and product
tests.
Resources
Rubric 8 for Evaluating Culminating
Activity
BLM 8.1 Shovel Arm Assembly
8.1_shovel arm.pdf
BLM 8.2 Boom Extension Design
8.2_boomextension.cwk
BLM 8.3 Case Study Outline
8.3_casestudy.cwk
1 cm square craft wood
wood dowels
craft sticks
syringes
plastic tubing
marbles
wooden wheels
cardboard sheets
metal jar lids
petroleum jelly
jigs (for joining pieces of glued wood)
Carpenter's glue
hacksaws
manually operated hand drills
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Toying With Efficiency
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
Subtask 8
280 mins
pencils
markers
hammers
tape
rulers
small metal objects
paint
Notes to Teacher
1. Review "Background Information" found in the Overview section, if necessary.
2. Two blackline masters have been included (Shovel Arm 8.1 and Boom Extension 8.2) for your convenience
but not for reproduction and distribution to students. These are just ideas of possible technical plans for
components that could be added to the mechanical device that was previously constructed in Subtask 8.
Students must create their own designs of a toy mechanical device that can move a given device the distance
outlined in the criteria. These blackline masters are just some added background/idea information for the
teacher.
3. A blackline master for students has been included to address design/construction criteria, how the teams will
work together, questions for individual reflection, and an overall timeline for this culminating activity. This
blackline master should serve as a guide for students to help keep them "on track."
4. Provide students with a product planning sheet on which they create their technical drawings and advise them
to include approximate measurements, types of materials to be used in the construction, and labels for the
various parts of the device (e.g., boom, base, etc.).
Teacher Reflections
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Appendices
Structures and Mechanisms
Mechanical Efficiency
Resource List:
Black Line Masters:
Rubrics:
Unit Expectation List and Expectation Summary:
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Resource List
Page 1
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
Rubric
Blackline Master / File
Rubric 1 for Gaining Leverage
3
ST 1
BLM 1.1 Notes About Levers
1.1_notes about levers.cwk
ST 1
Rubric 2a for Communication
3
ST 2
BLM 1.2 Gaining Leverage
1.2_Gaining Leverage.cwk
ST 1
Rubric 2b for Presentation
1
ST 2
BLM 1.3 Simple Machines - Levers
1.3.cwk
ST 1
Rubric 3 for Syringe System Investigation
2
ST 3
Rubric 4 for Investigation of Friction
2
ST 4
BLM 2.1 Comparison Chart
ST 2
2.1_comparison.cwk
Factors Affecting the Design and Purchase of Products
ST 5
BLM 2.2 Research Assignment
2.2_designing a product.cwk
ST 2
Rubric 5 for Velocity Ratio Investigations
2
ST 6
BLM 2.3 Student Checklist
2.3_rating scale.cwk
ST 2
Rubric 6 for MA/ME Investigations
2
ST 7
BLM 3.1 Syringe System Setup
3.1_syringesetup.cwk
ST 3
Rubric 7 for Hydraulic Test Lever Activity
2
ST 8
BLM 3.2 Syringe System Investigation
3.2.cwk
ST 3
Rubric 8 for Evaluating Culminating Activity
2
Toying With Efficiency
BLM 4.1 Slow Down
4.1_slowdown.cwk
ST 4
BLM 5.1 Velocity
5.1_Velocity.cwk
ST 5
BLM 5.2 Velocity Ratio
5.2_velocity ratio.cwk
ST 5
BLM 5.3 Velocity Ratio Using Levers
5.3_Levers VR.cwk
ST 5
BLM 5.4 Velocity Ratio Using Pulleys
5.4_PulleysVR.cwk
ST 5
BLM 5.5 Observations Table
5.5_observtable.cwk
ST 5
BLM 6.1 Mechanical Advantage - Levers
6.1_MALevers.cwk
ST 6
BLM 6.2 Mechanical Advantage - Pulleys
6.2_MAPulleys.cwk
ST 6
BLM 6.3 VR/MA with Levers
6.3_VRMALevers.cwk
ST 6
BLM 6.4 Summary Sheet (MA/VR)
6.4_SummarySheet.cwk
ST 6
BLM 6.5 Efficiency
6.5_Efficiency.cwk
ST 6
BLM 6.6 Observations Tables
6.6_observtable.cwk
ST 6
BLM 6.7 Multiple-Choice Test
6.7_MCTest.cwk
ST 6
BLM 6.8 Answer Sheet
6.8_Answers.cwk
ST 6
BLM 7.1 Hydraulic Test Lever - Tips
tips.pdf
BLM 7.1
ST 7
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Resource List
Page 2
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
BLM 7.2 Assembly Instructions
7.2_assembly1.pdf
ST 7
BLM 7.4 Base Frame Design
7.4_base frame.cwk
ST 7
BLM 7.5 Tower Frame Design
7.5_tower frame.cwk
ST 7
BLM 7.6 Boom Frame Design
7.6_boom frame.cwk
ST 7
BLM 7.7 Syringe Assembly
7.7_syringe assembly.cwk
ST 7
BLM 7.8 Side View / Complete Assembly
7.8_Side View All.cwk
ST 7
BLM 7.9 Instructions for Lever Test
7.9_testing steps.pdf
ST 7
BLM 8_ Assembly Instructions
8_assembly2.pdf
ST 7
BLM 8.1 Shovel Arm Assembly
8.1_shovel arm.pdf
ST 8
BLM 8.2 Boom Extension Design
8.2_boomextension.cwk
ST 8
BLM 8.3 Case Study Outline
8.3_casestudy.cwk
ST 8
Print
Commitment: Faith through Service
ST 2
Catholic Curriculum Cooperative
Mid year assessment unit with a focus on social justice
and consumerism.
Science and Technology 8
Carol Glegg, Peter Williams
ISBN 0-17-607497-4
Nelson Thomson Learning
Mechanical Advantage and Efficiency
Unit
Science and Technology 8
Kyn Barker, Steve Campbell, Gary Greenland,
Douglas Hayhoe, Doug Herridge, Kathy
Kubota-Zarivnij, Shelagh Reading, Lionel Sandner,
Beverley Williams
Pearson Education Canada - Addison Wesley
Mechanical Efficiency
Unit
Media
Efficiency of Energy Conversions
Unit
ACCESS
Investigates mechanical and biological systems to
determine and compare efficiencies of energy
conversion. By examining real and toy cars, various
types of electrical power generation, and packaging of
various foods, students learn to use efficiency
calculations.
Fluid Power Technology At Work
Unit
McIntyre Media
Brings the fluid power industry into your classroom. A
broad over view of many applications of hydaulics and
pneumatics is summarized.
Website
A World in Motion
Unit
http://www.schoolnet.ca/general/worldinmotion/e/ind
ex.html
This is an excellent interactive Canadian site created by
SAE, the Society of Automotive Engineers. It contains
metric lesson plans, definitions, recording sheets and
engineer’s links. It is divided into 5 units: Get Moving,
Power Up, Slow Down, Move Easy and Airborne.
Amusement Park Physics
Unit
http://www.learner.org/exhibits/parkphysics/
How do physics laws affect amusement park ride
design? In this exhibit, you'll have a chance to find out
by designing your own roller coaster. Plan it carefully--it
has to pass a safety inspection. You can also
experiment with bumper car collisions.
Cantilever Geometry
Unit
http://www.sheldonbrown.com/cantilever-geometry.h
tml
You cannot understand bicycle brakes unless you
understand mechanical advantage. Go to this site to
learn all about tuning your bike's brakes.
Friction - Science Museum in Minnesota
Unit
http://www.smm.org/sln/tf/f/friction/friction.html
Vollis Simpson is an artist who creates kinetic
sculptures and whirligigs. He uses bearings in all of his
spinning pieces so that they move smoothly. An
experiment here is a nice introduction to friction and
bearings.
History of Hydraulics
Unit
http://http://www.iihr.uiowa.edu/focusareas/history/h
ydraulics/
From the Iowa Institute of Hydraulic Research.
Pascal's Principle and Hydraulics
Unit
http://www.lerc.nasa.gov/www/K-12/WindTunnel/Acti
vities/Pascals_principle.html
Pascal's law is explained "that when there is an
increase in pressure at any point in a confined fluid,
there is any equal increase at every other point in the
container."
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Resource List
Page 3
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
Pressure
Unit
http://yesican.yorku.ca/home/press1.html
'Pressure' is a term often used in everyday life, for
example, we frequently speak of tire pressure, air
pressure, blood pressure, water pressure and so on.
The Pneumatic Tube and the History of
Unit
Pneumatic Devices
http://inventors.about.com/science/inventors/library
/inventors/blpneumatic.htm
A pneumatic device is any of various tools and
instruments that generate and utilize compressed air.
Visit this site to learn more about pneumatics.
Material
metre sticks
ST 1
metre sticks
ST 5
Newton spring scales
ST 4
petroleum jelly
Price: 20 cents/"squirt"
ST 8
plastic tubing
Prices: $1.25/m
(for syringes)
ST 8
pulleys (single)
ST 5
rollers (e.g., spools)
ST 4
string
ST 4
syringes
Prices: 10 CC 75 cents each
20 CC $1.50 each
35 CC $2.00 each
(different size pairs)
ST 8
1 cm square craft wood
Price: 1 cent/cm
(Jinx wood)
ST 8
syringes 10 mL and 20 mL
ST 7
1 cm square craft wood (60 cm in length)
ST 5
tape
ST 3
1 cm square craft wood (60 cm lengths)
ST 6
tape
ST 5
1 cm square craft wood (Jinx wood)
ST 7
tape or string to tie book to the metre stick
ST 1
2 L plastic pop bottles
ST 3
text books (optional)
ST 4
For student use when designing demonstrations (BLM
4.1 Part d).
2" x 4" blocks of wood (with hooks)
ST 4
Attach a hook at one end of each block of wood so that
a spring scale can be attached.
water
ST 3
3/16" doweling
ST 7
wheels
ST 4
4" x 1/4" bolts and nuts
ST 5
ST 8
4" x 1/4" bolts and nuts
ST 6
wood dowels
Price: 50 cents/90cm length
500 g masses
ST 4
ST 8
500 g masses
ST 5
wooden wheels
Price: 40 cents each
8.5" x 11" sheets of coarse sandpaper
ST 4
ball bearings
ST 4
book (e.g., dictionary)
ST 1
bricks (optional)
ST 4
For student use when designing demonstrations (BLM
4.1 Part d).
cardboard sheets
Price: 50 cents/20cmX20cm sheet
ST 8
cardboard squares (4 cm x 4 cm)
ST 3
craft sticks
Price: 1 cent each
ST 8
hardware catalogues
ST 1
heavy string
ST 5
heavy string
ST 6
household objects (see teacher notes)
ST 1
lubricants (e.g., oil, grease, or wax)
ST 4
marbles
Price: 10 cents each
ST 8
metal jar lids
Price: 25 cents each
ST 8
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Resource List
Page 4
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
Equipment / Manipulative
10 mL syringes
ST 3
20 mL syringes
ST 3
200 g masses
ST 3
200 g masses
ST 7
500 g masses
ST 6
cardboard gussets
ST 7
Carpenter's glue
ST 8
Carpenter's glue or glue guns
ST 7
clamps
ST 3
clear plastic tubing
ST 3
cm rulers
ST 7
electrical tape
ST 7
hacksaws
ST 8
hammers
ST 8
hand saws
ST 7
hand-powered drills with 13/64" or 7/32" bits
ST 7
jigs (for joining pieces of glued wood)
ST 8
manually operated hand drills
ST 8
markers
ST 8
metre sticks
ST 6
mitre boxes
ST 7
Newton spring scale
ST 6
paint
ST 8
pencils
ST 8
retort stand
ST 6
retort stands
ST 3
retort stands
ST 5
ring clamp
ST 6
ring clamps
ST 5
ruler (cm)
ST 6
rulers
ST 8
rulers (cm)
ST 5
small metal objects
(to be lifted by the mechanical device)
ST 8
small wooden blocks
ST 3
steel or plastic squares
ST 7
student desks
ST 5
student desks
ST 6
tape
(electrical and masking)
ST 8
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BLM 1.1 Notes About Levers
Levers
-are simple machines that make it easier or faster to move something
-all have a fulcrum (pivot point), load force (the force exerted by the
load), and effort force (the force required to move the load)
Effort Arm is the distance between the fulcrum and the effort.
Load Arm is the distance between the fulcrum and the load.
Three Classes Of Levers
Class 1
-the fulcrum is between the effort and the load
-can be used for power or precision (e.g., scissors, paint can lid
opener)
Effort
Load
Fulcrum
Class 2
-the load is between the effort and the fulcrum
-moves a large load with little effort (e.g., wheelbarrow)
Load
Effort
Fulcrum
Class 3
and
-the fulcrum is at one end and the effort is exerted between the load
fulcrum, as a result the load arm is always longer than the effort arm
-makes movement magnified, not lighter to lift (e.g., hockey stick,
fishing
rod)
Effort
Fulcrum
Load
BLM 1.2 Gaining Leverage (Three Classes of Levers)
Investigation: Investigate the advantages and efficiency of the three classes of
levers.
Materials: metre stick, a book (e.g., dictionary), tape, desk top
Procedure:
Class 1 Lever (fulcrum in the middle)
i) Place the metre stick with half the length on the desk and the other half extending
over the edge. Use the desk's edge as the fulcrum.
ii) Place the book on the end of the load arm (end that is lying on the desk).
iii) Push down on the effort arm (end extended over the edge).
Try this with the fulcrum at two or three different distances from the load or effort
forces.
Class 2 Lever (load in the middle)
i) Tape the book to the middle of the metre stick, so it is attached below the stick.
ii) Put one end of the metre stick on the desk and hold the other end up with book
hanging below.
iii) Try to lift the book using the metre stick while it is hanging at a few different
places along the stick.
Class 3 Lever (effort in the middle)
i) Tie the book beneath the far end of the metre stick.
ii) While holding the metre stick's end in place on the desk, try to lift the book with
the overhanging extension.
Observations:
1. Draw a diagram labelling the location of the load, effort, and fulcrum for each.
2. Record observations for each activity. Be sure to include the direction of force of
the effort and load in each activity. Explain observations of the advantages or
disadvantages of where the fulcrum, load, and effort are.
Conclusion:
What conclusions are made about the three classes of levers?
BLM 1.3 Simple Machines That Are Levers
First Class Levers
Second Class Levers
Third Class Levers
BLM 2.1 Comparison Chart
Factors Affecting Design/
Purchase of Products
moral/ethical
efficiency
economic
environmental
ergonomic
social
aesthetic
material costs
safety
durability
Electric Car
Car with Combustion
Engine
BLM 2.2 Independent Research Assignment
Factors Affecting the Design, Marketing, and Purchase
of Consumer Products
You are required to select one of the following three topics and complete a research report to
address the issue outlined for you. Please pay close attention to the research and report-writing
criteria that is provided with the outline of each topic. A student self-assessment checklist (BLM
2.3) is also being provided to you so that you can use it both during and after your work on this
assignment to help to ensure that you are completing/have completed this assignment according
the criteria and outline that has been provided for you.
Option A
In a single sentence, define “ergonomics.” Use an essay format of at least five paragraphs to
describe a product that has some ergonomic design features that take into account the needs and
comfort of the potential consumer. In the first paragraph, describe the original design of the
product. In subsequent paragraphs, outline ergonomic-related factors such as materials,
durability, aesthetics, health issues, safety, efficiency, and physical attributes of the potential
consumer, in relation to this product. Suggest modifications that you feel would help to improve
the ergonomic design of the product. In your closing paragraph, explain why you think the new
design, that you have suggested, is more beneficial to consumers than the original design.
Option B
Develop a marketing plan/strategy for a hypothetical product (cannot be something that has
been advertised before), that incorporates some of the important factors that affect the design
and purchase of consumer products (that were discussed as a class earlier in this subtask). Use an
essay format of at least five paragraphs to describe the hypothetical product and the reasons why
a potential consumer would want to purchase it. In the first paragraph, provide a brief desciption
of this “new” product and what purpose it could serve in the life of the potential consumer. In
subsequent paragraphs, outline the “selling features” of this product. Use appropriate descriptive
language and be persuasive. In the concluding paragraph, to reiterate the “strengths” of your
product identify what it is that makes your product unique and sets it apart from anything else that
is currently available (or not available) on the market, and why they should buy it right away.
Option C
Select a product manual for a product that you have in your home or select a help screen for
a particular computer program and read through it thoroughly. Then locate another manual for a
different product or another help screen and review it. Set up a comparison chart, using a
computer program (e.g., Microsoft Publisher, Microsoft Excel, or Corel WordPerfect), with
category headings such as product name, product description, clarity of manuals or help screens,
thoroughness, general “user-friendliness,” and suggested improvements (to make manuals or help
screens easier to use). You should come up with a rating scale (and a legend to explain the
scale, which could be added under the chart) that could be used under the category headings of
clarity of manuals or help screens, thoroughness, and general “user-friendliness.”
After you have completed your work for Option A, B, or C, you will be required to present the
results of your work to your classmates. Refer to your self-assessment checklist for specific
directions regarding your presentation. You will be required to take notes in your learning log
during classmates’ presentations to demonstrate what you have learned.
BLM 2.3 Student Self-Assessment Checklist
Student Name:
Date:
__________________
__________________
____
A.
Participated, regularly, in the class discussion leading up to the research
assignment.
____
B.
Identified important attributes of consumer products (e.g., personal,
environmental, economic, product quality, moral or ethical issues) that
be considered before creating and purchasing such products
____
C.
Demonstrated an understanding of the new concepts of “aesthetics” and
“ergonomics” through involvement in class discussion.
____
D.
Examined the strengths and weaknesses of a consumer product in a
“Consumer Report” or completed a comparison chart for electric cars versus
cars with combustion engines according to the criteria provided by the
E.
Used a variety of suitable, informative resources to complete research
assignment.
should
(orally).
teacher.
____
____
F.
paragraphs,
developed a well-
Used proper essay format, including strong opening and closing
and at least five paragraphs that support the topic OR
designed chart with appropriate headings and a legend, containing relevant
information.
____
G.
Completed an edit of the essay OR chart, paying particular attention to
sentence structure (if applicable), spelling, and overall content.
____
H.
Presented the research report to the class in a manner that reflected
preparedness, knowledge and understanding of the topic, poise,
and eye contact with the audience.
I.
Followed instructions carefully and met deadlines.
confidence,
____
BLM 3.1 Syringe System Setup
200 g mass
wooden object
BLM 3.2 Syringe System Investigation
1. Experiment setup:
i) Clamp a 20 mL-syringe to a retort stand.
ii) Using clear plastic tubing connect a 10 mL-syringe and tape it to the desk top.
iii) Pull the plunger up fully, filling the syringe with air. Make sure the 10 mL-syringe's plunger is
totally pushed in.
iv) To the top of the plunger add a cardboard square to act as a platform for a 200 g mass.
v) In front of the 10 mL-syringe place an object (e.g. small block). Place the 200 g mass on top of
the 20 mL-syringe and observe.
vi) Measure the distance the object was moved.
2. Repeat the same experiment but this time clamp the 10 mL-syringe to the retort stand and
tape the 20 mL-syringe to the desk top.
3. Repeat the same experiments, this time filling the clamped syringe with water in the place of
the air.
4. Draw a diagram for each experiment and record your observations for each experiment in the
learning log. Be sure to include the following:
i) Compare your observations for all four experiments.
ii) What conclusions can be made for the effects of pressure in an closed system?
iii) What advantages are there to a smaller or larger piston?
iv) What comparison is there for a hydraulic system to a pneumatic system?
v) Explain real life situations when and how a hydraulic system or pneumatic system would be
used.
BLM 4.1 SLOW DOWN
AN INVESTIGATION INTO THE FORCE OF FRICTION
Procedure:
(a) Take 2 blocks of wood (2” x 4” pieces) and rub one of the smooth surfaces of
one block against a smooth surface of the other block repeatedly and quickly for
about 15 seconds. Now touch the surfaces with your fingers to get a sense of their
temperatures. Record your findings by using a single sentence in the
“Observations” section below.
(b) Push one of the blocks of wood over a sheet sandpaper that is lying on a desk
top. Now push the same block over the desktop surface. Note how the nature of
the surfaces affects friction and record your observations in the “Observations”
section below.
(c) Find out whether surface area shared when two objects are in contact with each
other affects the amount of force required to overcome friction. Place one of the
wooden blocks so that is lying with its largest surface in contact with the same
sheet of sandpaper (as in (b) above), with a 500 g mass mounted on top. Attach a
spring scale to the hook at one end of the piece of wood and drag the block across
the sheet of sandpaper. Record the force required to move the wooden block
across the sandpaper. Now tip the block up on its “side” so that a smaller surface
area can be slid across the sandpaper. Place the 500 g mass on top of the block.
Again measure the force required to move the block by hooking the spring scale
onto the wooden block and dragging it across the sandpaper. Record the forces
required to move the wooden block under both conditions outlined above in the
“Observations” section.
(d) Devise some simple demonstrations for your teacher and classmates to show
how the following actions or materials help reduce friction:
(i) polishing (or sanding)
(ii) using a lubricant such as oil, grease, or wax.
(iii) using rollers or ball bearings
Your teacher will supply you with some of the necessary materials to help you set
up your demonstrations. You may need to find some other common classroom
supplies that will help you put together these demonstrations. Your teacher will ask
you to share at least one of the demonstrations that you create with a small group of
students (as directed by your teacher).
BLM 4.1 SLOW DOWN (cont'd)
Observations and Conclusions:
Write a brief description of your observations and conclusions from each of the
above steps in the procedure, in the space provided. (Attach an extra sheet of paper
if necessary.)
_________________________________________________________________
_
_________________________________________________________________
_
_________________________________________________________________
_
_________________________________________________________________
_
_________________________________________________________________
_
_________________________________________________________________
_
_________________________________________________________________
_
_________________________________________________________________
_
_________________________________________________________________
_
_________________________________________________________________
_
_________________________________________________________________
_
_________________________________________________________________
_
_________________________________________________________________
_
_________________________________________________________________
_
_________________________________________________________________
_
Follow-up Questions
1. State two reasons why it is a good idea to carry a heavy bag of sand in the trunk
of your car in the winter.
_________________________________________________________________
_
_________________________________________________________________
_
_________________________________________________________________
_
_________________________________________________________________
_
_________________________________________________________________
_
_________________________________________________________________
_
_________________________________________________________________
_
2. Explain why we often rub our hands together on a cold day.
_________________________________________________________________
_
_________________________________________________________________
_
_________________________________________________________________
_
_________________________________________________________________
_
BLM 5.1 VELOCITY
The purpose of subtask 5 is for you to gain an understanding of velocity and
then be able to calculate velocity ratios of different devices.
Force, Time, Distance
In order to begin our study we need to understand the terms force, distance,
time, and speed.
Particle Theory states that all matter consists of tiny particles which are in
constant motion. Because these particles are moving a certain distance in a given
time, they have speed.
Force is defined as a push or a pull. Forces have both magnitude (size) and
direction.
Force diagrams can be drawn to show forces which affect an object. Arrows
are used to show these forces. Place arrows on these diagrams to show the
forces at play.
BLM 5.1 VELOCITY (continued)
Time describes how long an action takes place and may be measured in
seconds, minutes, hours, etc.
Distance is a measure of how far an object moves when a force is applied.
Distance is stated in units of linear measure (cm, m, km, etc.).
Speed is a measure of how far an object moves in a certain period of time.
What would be the speed of this bouncing ball?
Speed = _________ cm/s
Velocity is speed in a given direction.
It is velocity that we will be using in this unit. You will need to be able to
calculate this value.
Use the following formula for finding velocity.
V = D/t
V= velocity
D= distance
t = time
A car travels east, from Toronto, on the 401 for a distance of 120 km. It takes
1 hour and 15 minutes to reach its destination. What is its velocity?
BLM 5.2 VELOCITY RATIO
Velocity Ratio is the comparison of the distance a load force moves with the
distance the effort force moves.
To begin our study of velocity ratio let us focus our attention on the lever.
Note:
1. Both the load and the effort move for the same amount of time.
2. The effort moves farther than the load does.
Measure the distance each force moves.
The load force moves ______ cm and the effort force moves ______cm.
To calculate velocity ratio, divide the distance that the effort force moves by
the distance the load force moves. Note: No units are used for velocity ratio (only a
number).
Velocity Ratio = Distance effort force moves
Distance load force moves
Use the formula to find the velocity ratio of the lever. (Do your calculations in the
space provided.)
BLM 5.2 VELOCITY RATIO (continued)
Now let's look at the pulley.
SCALE
Use the distances given in the diagrams to calculate the velocity ratios of the
pulleys. (Do your work in the space provided.)
Single Fixed Pulley
Double Fixed Pulley
1 cm = 1 m
BLM 5.2 VELOCITY RATIO (continued)
USING PULLEYS
It is time now to gather first hand data using real pulleys.
MATERIALS (per group):
- 1 cm x 60 cm piece of wood
- 2 single pulleys
- 75 to 100 cm heavy string(ie. meat cord)
- metre stick
- 2 desks
METHOD:
1. Place a 1cm x 1cm piece of wood across the space between two desks.
2. Fasten a single fixed pulley to this beam.
3. Tie a weight to one end of a length (75 to 100 cm) of heavy string.
4. Feed the string through the pulley.
5. Place a metre stick behind the pulley.
6. Holding the string between your thumb and index finger, haul the weight
up until the bottom of the weight is level with (at same point on the metre
stick your thumb is.)
7. Note exactly where this point (benchmark) is on the metre stick and record
this point.
8. Haul the weight up from this benchmark by pulling down on the string.
(Use the distances indicated in the observations chart.)
9. Carefully observe how far your thumb has moved down from the
benchmark and record the values in the observations chart.
10. Fasten a double fixed pulley to the beam and repeat steps 3 - 9.
OBSERVATIONS:
Benchmark Point ________
BLM 5.2 VELOCITY RATIO (continued)
DISTANCE WEIGHT IS HAULED UP
(Load Force)
DISTANCE THUMB MOVES DOWN
(Effort Force)
Single Fixed Pulley
Double Fixed Pulley
5 cm
_______ cm
_______ cm
10 cm
_______ cm
_______ cm
15 cm
_______ cm
_______ cm
Average Distance = _________ cm
Average Distance =
______ cm
Average Distance =
______ cm
ANALYSIS:
Using the average distances the load and effort forces moved, find the
velocity ratio for both pulleys.
Single Fixed Pulley
VR = Distance effort force moves
Distance load force moves
VR = _____________________
Double Fixed Pulley
VR = Distance effort force moves
Distance load force moves
VR = _____________________
VR =
VR =
CONCLUSIONS:
Look back in the table at the average values. For each pulley note the
number of cm the effort force moves in order to move the load force 10 cm.
Why might a velocity ratio equal to one be good?
What advantage might a velocity ratio greater than one have?
As you work your way through subtask 7 look for a relationship between the
length of rope you pull and the effort required to lift an object.
BLM 5.3 Velocity Ratio Using Levers
MATERIALS (per group):
- retort stand
- ring clamp
- 4" x 1/4" bolt and nut
- tape
- 30 cm wooden ruler
- 2 metre sticks
PROCEDURE:
1. Fasten a ring clamp to a retort stand.
2. Tape a 1/4” bolt along the top surface of the ring (parallel). Allow part of
the
bolt to protrude past the edge of the ring (so it “sticks out”), on the side
opposite
to the retort stand. This will serve as your fulcrum.
3. Ensure that the retort stand is placed on a flat, level surface.
4. Drill 1/4” holes every 2 cm, in both directions, starting from the 15 cm mark
of the ruler.
5. Using the bolt as your fulcrum, slide the ruler onto the end of the
protruding
bolt, through the centre hole of the ruler. This ruler will serve as
your lever.
6. Thread the nut onto the bolt and tighten enough to stabilize the lever but
not
to impede its movement.
7. Level the lever horizontally, as accurately as possible.
8. Hold a metre stick vertically at each end of the levelled lever (to be used as
a
measuring tool for the movement of the lever). One of two students could
hold
each metre stick.
9. Move one end of the lever down 6 cm. This is the effort arm.
10. Observe and record how far the other end of the lever moves up.
11. Change the lengths of the arms of the lever by moving the lever to each of
the different holes, recording your data as you proceed.
12. Repeat steps 6 to 11 until all holes on the ruler have been used.
OBSERVATIONS:
Create a table to record the results of your investigations. Your table will require 4
columns and at least 4 rows.
BLM 5.3 Velocity Ratio Using Levers (continued)
ANALYSIS:
Velocity Ratio = Distance Effort Force Moves
Distance Load Force Moves
Calculate the velocity ratio of the lever using the headings in the table below.
Data is found in the above table: of observations.
EFFORT ARM LONGER
ARMS EQUAL
EFFORT ARM SHORTER
BLM 5.4 Velocity Ratio Using Pulleys
MATERIALS (per group):
- 1 cm x 60 cm piece of wood
- 2 single pulleys
- 75 to 100 cm heavy string (i.e., meat cord)
- metre stick
- 2 desks
- 500 g mass
METHOD:
1. Place a 1 cm x 1 cm piece of wood across the space between two desks.
2. Fasten a single fixed pulley to this beam.
3. Tie a 500 g mass to one end of a length (75 to 100 cm) of heavy string.
4. Feed the string through the pulley.
5. Place a metre stick behind the pulley.
6. Holding the string between your thumb and index finger, haul the load
(500 g
mass) up until the bottom of the load is level with (at same point on
the
metre stick) your thumb.
7. Note exactly where this point (benchmark) is on the metre stick and record
this point.
8. Haul the load up from this benchmark by pulling down on the string.
(Use the distances indicated in the observations chart.)
9. Carefully observe how far your thumb has moved down from the
benchmark and record the values in the observations chart.
10. Fasten a double fixed pulley to the beam and repeat steps 3 to 9.
OBSERVATIONS:
Benchmark Point ________
BLM 5.4 Velocity Ratio Using Pulleys (cont'd)
DISTANCE 500g MASS IS HAULED UP
(Load Force)
DISTANCE THUMB MOVES DOWN
(Effort Force)
Single Fixed Pulley
Double Fixed Pulley
5 cm
_______ cm
_______ cm
10 cm
_______ cm
_______ cm
15 cm
_______ cm
_______ cm
Average Distance = _________ cm
Average Distance =
______ cm
Average Distance =
______ cm
ANALYSIS:
Using the average distances the load and effort forces moved, find the velocity ratio
for both pulleys.
Single Fixed Pulley
VR = Distance effort force moves
Double Fixed Pulley
VR = Distance effort force
moves
Distance load force moves
moves
VR = ________
VR =
Distance load force
VR = ________
VR =
CONCLUSIONS:
Look back in the table at the average values. For each pulley, note the number of
cm
the effort force moves in order to move the load force 10 cm.
Why might a velocity ratio equal to one be good?
What advantage might a velocity ratio greater than one have?
As you work your way through subtask 6 look for a relationship between the length
of
rope you pull and the effort required to lift an object.
BLM 5.5 Observations Table for BLM 5.3 (Adaptation)
LENGTH OF EFFORT
ARM
LENGTH OF LOAD
ARM
DISTANCE EFFORT
FORCE (ARM)
MOVES
DISTANCE LOAD
FORCE (ARM)
MOVES
15 cm
15 cm
6 cm
_____ cm
17 cm
_____ cm
6 cm
_____ cm
13 cm
_____ cm
6 cm
_____ cm
BLM 6.1 Mechanical Advantage Using Levers
MATERIALS (per group):
- retort stand
- ring clamp
- 4" x 1/4" bolt and nut
- 30 cm wooden ruler
- 500 g mass
- Tubular spring scale
METHOD:
1. Follow steps 1 to 6 in the method of the velocity ratio investigation using
levers.
2. Hang the 500 g mass on the outside hole of the load arm.
3. Hook the Tubular spring scale to the outside hole of the effort arm.
4. Level the lever.
5. Pull evenly on the spring scale to keep the lever level.
6. Observe and record the effort force.
7. Change the length of the effort arm by moving the lever to different holes.
(Test your apparatus with the effort arm length equal to, greater than, and
less
than the length of the load arm.)
8. Repeat steps 4 to 6.
OBSERVATIONS:
Create a table to record your observations.
BLM 6.1
Mechanical Advantage Using Levers (cont'd)
ANALYSIS:
Mechanical Advantage = Load force
Effort force
Use the equation and the information in this table to find the mechanical advantage
of the lever.
Effort arm longer
Arms of equal length
Effort arm shorter
MA = LF / EF
MA = LF / EF
MA = LF / EF
BLM 6.2 Mechanical Advantage Using Pulleys
MATERIALS (per group):
- 1 cm x 60 cm piece of wood
- 2 single pulleys
- 75 to 100 cm heavy string
- 1 x 500 g mass
- 1 tubular spring scale
- 2 desks
PROCEDURE:
1. Place a piece of 1 cm wood across the space between two desks.
2. Fasten a single fixed pulley to this beam.
3. Tie a 500 g mass to one end of a length (75 to 100 cm) of heavy string.
4. Feed the string through the pulley. Tie the other end of the string to the
hook of a tubular spring scale. Zero out the spring scale. (Turn the
adjusting nut until the scale reads zero Newtons.)
5. With the load (500 g mass) resting on a surface pull on the spring scale
only
enough to take the slack out of the string. Make sure the scale is reading
zero newtons.
6. Slowly pull on the newton spring scale and cause the load to be raised
off the surface on which it is resting.
7. Note the number of newtons of force required to raise the load and
record this value in your observation chart.
8. Repeat two more times and record.
9. Tie a double fixed pulley to the beam and repeat steps 3 to 9.
OBSERVATIONS:
Mass of Object = ___________ g
Load force = mass (in grams) / 100 = ____________ N
***Remember: 10 N of force will lift a 1Kg mass.
Create a table to record your observations.
1. Give the table a title.
2. You will be recording data for a single fixed pulley and a double fixed
pulley.
3. Record the results of three trials and an average for each pulley.
BLM 6.2 Mechanical Advantage Using Pulleys (continued)
ANALYSIS:
To find the mechanical advantage, divide the load force by the effort force.
(Use the average effort force.)
Single Pulley
MA = LF/EF
MA = ______
MA =
Double Pulley
MA= LF/EF
MA = _______
MA =
Note: Mechanical Advantage is just a number. (i.e., MA = 1, not MA = 1 N)
BLM 6.3 Velocity Ratio/Mechanical Advantage With Levers
When looking at levers, we must consider the sizes of the forces and the lengths of
the arms of the lever.
When the effort force is less than the load force, the lever has a mechanical
advantage (for force). This advantage is gained by using a lever with an effort arm
longer than its load arm.
If the two arms are the same length, the forces would also be equal.
That is, it would take an effort of ___________ N to move a load of 10 N.
In this example, the mechanical advantage would be equal to 1.
MA = LF/EF
MA = ? ____/ ____
MA = 1
Therefore, if the effort force is less than the load force, the mechanical advantage
would be ____________ (greater/less) than 1.
If the effort force is greater than the load force, the mechanical advantage would be
_____________ (greater/less) than 1.
Another way to look at mechanical advantage is to consider the lengths of the
load arm and the effort arm.
Levers with effort arms longer than their load arms have a mechanical
advantage which is greater than 1.
Therefore, levers with effort arms __________ (longer/shorter) than their
load arms have a mechanical advantage less than one.
MA = length of effort arm
length of load arm
BLM 6.3 Velocity Ratio/Mechanical Advantage With Levers
(cont.)
What would be the mechanical advantage of a lever whose effort arm is 90 cm and
its load arm is 10 cm?
ANSWER: ______
For each lever indicate if the mechanical advantage and velocity ratio is
greater than, equal to, or less than 1 by using the appropriate symbol (>, <, =) in the
blank. Give the name of a real life example of this lever.
MA ____ 1
VR ____ 1
___________
Example:
MA ____ 1
VR ____ 1
___________
Example:
MA ____ 1
VR ____ 1
___________
Example:
MA ____ 1
VR ____ 1
___________
Example:
MA ____ 1
VR ____ 1
___________
Example:
Some machines offer an advantage of moving a larger load with less effort.
These machines have a _______________ (force, velocity) advantage.
Other machines require greater effort to move a smaller load but a
movement of the effort force results in a greater movement of the load. These
machines have a ______________ (force, velocity) advantage.
BLM 6.4 SUMMARY SHEET
Mechanical Advantage/Velocity Ratio
Complete the following organizer by filling each cell with "yes" or "no."
1st Class Lever 2nd Class Lever 3rd Class Lever
Single Fixed
Pulley
Double Fixed
Pulley
Mechanical
Advantage
EF<LF
Velocity Ratio
VR > 1
Study the organizer. Can you see a relationship between mechanical advantage and
velocity ratio? What is it?
You may have heard the expression, "You can't get something for nothing." This is true of
machines.
In order to reduce the size of the ________ force needed to move a load, that force must
be applied over a greater ____________.
BLM 6.5 EFFICIENCY
To determine how efficient a machine is, we divide its mechanical advantage by its
velocity ratio. If we multiply this result by 100 we will state our answer as a per cent.
Percent Efficiency = Mechanical advantage x 100
Velocity ratio
What would the percentage efficiency of a machine with a mechanical advantage of
3 and a velocity ratio of 3.
PE = MA/ VR x 100
= _______ x 100
= _______ %
No machine is 100% efficient. What is one factor that reduces the efficiency of a
machine?
How might this factor be diminished?
BLM 6.6 Observations Table for BLM 6.1 (Adaptations)
Length of Effort Arm
(cm)
Length of Load Arm
(cm)
Load Force (N)
Effort Force (N)
15
17
13
Observations Table for BLM 6.2 (Adaptations)
Single Fixed Pulley
Double Fixed Pulley
Trial #1 ________ N
Trial #1 ________ N
Trial #2 ________ N
Trial #2 ________ N
Trial #3 ________ N
Trial #3 ________ N
Average ________ N
Average ________ N
BLM 6.7 MULTIPLE-CHOICE TEST
Circle the letter of the most correct response. Select only one response for
each question. Refer to the following formulas when doing some of the
questions.
1. Effort force x length of effort arm = Load force x length of load arm
2. VR = Distance effort force moves
Distance load force moves
3. MA = Length of effort arm
Length of load arm
4. MA = Load force
Effort force
5. Percentage Efficiency = MA x 100%
VR
1. Which of the following is true of first-class levers?
A) The fulcrum is between the effort force and load force.
B) The fulcrum could be placed closer to the effort force giving the lever a
velocity advantage.
C) The fulcrum could be placed closer to the load giving the lever a force
advantage.
D) All of the above
E) Only A & C
2. An ergonomically designed object
A) is safer for people to use.
B) works more efficiently and easily.
C) is more attractive than functional.
D) Only A & B
E) Only A & C
BLM 6.7 MULTIPLE-CHOICE TEST (continued)
3. When using a single fixed pulley
A) the effort force equals the load force.
B) the effort force is greater than the load force.
C) the effort force is less than the load force.
D) the velocity ratio is >1.
E) None of the above.
4. A double fixed pulley is being used to raise a weight of 60 N. What effort force is
required?
A) 60 N
B) 30 N
C) 20 N
D) 15 N
E) None of the above
5. A double fixed pulley is being used to raise a weight of 60 N to a height of 3 m.
How many metres of rope must be pulled through the pulley?
A) 3 m
B) 1.5 m
C) 6 m
D) 9 m
E) None of the above
6. What would be the mechanical advantage of a lever with an effort arm 2 metres
long and a load arm 0.5 metres long?
A) 4
B) 0.25
C) 2
D) 1
E) None of the above
BLM 6.7 MULTIPLE-CHOICE TEST (continued)
7. The mechanical advantage of a double fixed pulley requiring an effort of 15 N to
raise a load of 45 N would be?
A) 2.5
B) 0.34
C) 1.5
D) 3
E) None of the above
8. What would the Percentage Efficiency of a mechanism if its mechanical
advantage is 2.7 and its velocity ratio is 3?
A) 90%
B) 87%
C) 100%
D) 88.3%
E) None of the above
9. A liquid, in a closed system,
A) distributes force evenly to the entire inside surface area of the container.
B) is virtually not able to be compressed.
C) is compressible.
D) A & B
E) A & C
10. Which of the following is true about levers?
A) The first-class lever has its fulcrum between its load and the force.
B) A wheelbarrow is an example of a second class lever.
C) The effort in a third-class lever is between the load and the force.
D) All of the above
E) Only A & C
BLM 6.7 MULTIPLE-CHOICE TEST (continued)
11. The third-class lever
A) has a velocity ratio less than 1.
B) has a mechanical advantage greater than 1.
C) uses a large effort force to move a smaller load.
D) All of the above
E) Only A & C
12. A mechanism operated by a hydraulic system has a load arm that is 10 cm long
and an effort arm which is 5 cm long. How many N of force will the hydraulic system
need to produce to raise an object which has a load force of 50 N?
A) 50 N
B) 500 N
C) 100 N
D) 5 N
E) 2 N
BLM 6.8 ANSWER SHEET
BLM 5.1
ARROWS----------- Rock-----------rock down; ground up
Seesaw-------both people down
Pulley----------rope down; weight down; pulley hanger up;
pulley down
Scissors------handles together; blades together; paper
opposite to blades
BOUNCING BALL---Speed=32 cm/s
CAR---Speed=96 km/h
BLM 5.2
VELOCITY
load force moves (.5 cm); effort force moves (2 cm)
velocity ratio=4
VELOCITY RATIO (Continued)
Single fixed pulley------VR=1
Double fixed pulley-----VR=3
VR= 1 is good because a load which is able to be lifted can be moved
more quickly.
VR>1 is good because a load which is too heavy to be lifted
without a machine can be lifted.
BLM 6.3
MECHANICAL ADVANTAGE
Effort of 10 N to move a load of 10 N
MA=10/10
Effort<load then MA is (greater) than 1
Effort>load then MA is (less) than 1
Effort arms (shorter) than load arms have MA<1
MA for lever with effort arm 90 cm and load arm 10 cm is (9)
>,=,< ----------------lever 1---MA(=)--VR(=)
lever 2---MA(>)--VR(>)
lever 3---MA(>) --VR(>)
lever 4---MA(<)--VR(<)
lever 5---MA(<)--VR(<)
Machines that move larger load with less effort = (force) advantage
Machines that move smaller load a greater distance = (velocity)
advantage
BLM 6.8 ANSWER SHEET (continued)
BLM 6.5
EFFICIENCY
PE=MA/VR
=3/3*100
= 100%
Efficiency is reduced by FRICTION
Friction can be diminished by using BEARINGS or LUBRICATION
BLM 6.4
SUMMARY
EF<LF---------yes-----yes-----no-----no-----yes
VR>1----------yes-----yes-----no-----no-----yes
Relationship-------If MA=1 then VR=1
If MA<1 then VR<1
If MA>1 then VR>1
In order to reduce the size of the (effort) force needed to move a load,
that force must be applied over a greater (distance).
BLM 6.7
MULTIPLE CHOICE TEST
1--D
2--D
3--A
4--C
5--D
6--A
7--D
8--A
9--D
10--D
11--E
12--C
BLM 7.1 Hydraulic Test Lever (First Class)
This machine is constructed with 1 cm2 craft wood. 3/16 doweling is used for
all pivot points. This unit can be assembled using carpenter’s wood glue with
gussets. Tape a steel square to the work surface to use when squaring frames.
A small plastic square from a geometry set works well to square cross braces.
Tips:
C
When working with 1 cm2 craft wood, 3/16" dowel is easier to work with
than 1/4". Make the holes a little larger than the dowel by using a
13/64" (best) or 7/32" drill so that pivot pins can be inserted and
removed easily.
C
When drilling pivot holes in parallel parts (such as the sides of the
boom), do so before assembling. Mark one side, and then tape it securely
to the other side with masking tape and drill both at once. This will
ensure that all of the holes align properly.
C
When drilling holes close to the end of a piece of wood, either drill before
cutting or the cut piece extra long, drill the hole, and then trim to correct
size. This will prevent the end from splitting.
C
Hydraulic or pneumatic cylinders need to be able to pivot slightly on both
ends when moving something that arcs (such as a lever) or they will
bind.
C
Attaching the end of the syringe to a pivot can be difficult. One effective
way is to cut the thumb piece off of the plunger and then carefully drill a
pivot hole through the middle of the X shaped stem about ½ cm from the
end.
C
As part of the assembly of these machines, the joints can be further
strengthened using gussets fastened with wood glue if so desired.
C
The measurements given for the assembly of these machines are based
on using a 20 mL syringe. However, the syringe used for the input force
in the hydraulic system is a 10 mL syringe.
C
If this machine is going to be used to lift heavy loads, extend the sides of
the base frame to the rear about 10 cm as shown on the plan. This will
accommodate a counterweight.
BLM 7.2 Assembly Instructions
Base Frame
Cut five 8 cm crosspieces and two 25 cm sides (35 cm if you want
counter balance supports). Glue together being careful to follow
layout instructions. There will be a 1 cm gap left in the center
where the tower will be inserted. Make sure the frame is squared
and flat as you glue it.
Tower
Cut two 28 cm sides and three 6 cm crosspieces. Also cut two 450
angle supports 7 cm long. Tape the side pieces together with
masking tape and drill the pivot hole 22 cm from bottom. Glue the
bottom horizontal crosspiece first. Then add an angle brace. The
next horizontal support is glued at the top and so on. Square each
horizontal support as you go.
When the tower is made, glue it into the empty space in the center
of the base making sure it is at a 900 angle. Add two 450 supports
on the front end of the tower. They need to reach from the cross
brace to the tower.
Boom
Cut two side rails 50 cm long. Tape securely together and mark
hole layout as shown on diagram. At the effort end of boom the
first hole should be drilled 2 cm from end and then four more at 2
cm intervals. The boom fulcrum hole is drilled 14 cm from effort
end. Be careful to drill both holes through the center of the wood
or the boom will be tilted to one side. The holes at the load end of
the boom are used to change the advantage of the lever as well as
adjustment pivot points for later attachments. They also are drilled
at 2 cm centers. There are three 2 cm cross braces (note that there
is an end brace on the work end only). Make sure the pieces are
flat and squared, then glue them. The boom can now be mounted
on the tower frame.
BLM 7.3 Assembly Instructions
Hydraulic/Pneumatic Cylinder Assembly
Cut two 14 cm side pieces. Tape together and drill a pivot hole 1
cm from one end. Put one on either side of a 20mL syringe with the
two pieces of wood butting against the protruding finger supports of
the cylinder. Insert a 3/16" pivot pin through the holes to ensure
they align. Wrap with electrical tape near top and bottom of the
cylinder. Remove the plunger from the cylinder and carefully use a
hacksaw to cut the thumb piece off flush at the end. Drill a pivot
hole through the X shaped plunger ½ cm from the end. If this is
going to be a hydraulic system, load the syringes and tubing with
water now. Cut two 12 cm pieces for the pivot assembly. Tape
together and drill a pivot hole 4 cm from the end. Glue in place 1
cm inside base frame (they should line up with the tower uprights).
Line up the holes with those on the wooden cylinder supports and
insert a pivot pin through the holes. Insert another pivot pin into
one set of the boom adjustment holes and through the cut end of
the plunger. Your machine is now ready for testing!
BLM 7.4 Ba se Frame Design
(Framework uses 1cm x 1cm craftwood.
All dowelling is 3/16” in diameter.)
BLM 7.5 Tower Frame Design
(Framework uses 1 cm x 1 cm craftwood.
All doweling is 3/16” in diameter.)
BLM 7.6 Boom Frame Design
(Framework uses 1cm x 1cm craftwood.
All doweling is 3/16” in diameter.)
Lever advantage
adjustment holes
(effort end of boom)
spaced at 2 cm
intervals for 3/16”
Boom Pivot
Hole (for
connecting
Optional lever
advantage
adjustment holes
(load end of boom)
spaced at 2 cm
Boom Design
BLM 7.7 Syringe Assembly
Use a 20 mL syringe.
Drill 13/64” or 7/32” holes for 3/ 16”
dowel pin (before making full assembly)
1 cm from the end of each piece of
craftwood.
Secure wood to syringe with electrical
tape.
Cut thumbpress off of plunger for this
syringe only.
Drill 13/64” or 7/32” hole through end
of plunger (where “X” is marked).
Tape
Tape
BLM 7 .8 Side View of Complete Assembly
Top Pivot
Boom
Load End
Tower
20 mL
Syringe
7
Bottom Pivot
Assembly
Base
cm
Tower Suppor ts
BLM 7.9 Instructions for Testing the Hydraulic
Lever
Now that you have completed the construction of your hydraulic lever, it is time
to test it!
1/ Create a table or data chart for the information that you will be finding and
calculating as part of this testing procedure. Use an appropriate computer
program or create the table by hand (according to the instructions of your
teacher).
You will be:
a) measuring and recording “EA” (distance from where effort force is applied
to fulcrum), and “RA” (distance from the load force to fulcrum), recording “R”
(load force), and calculating “E” (effort force by using the formula E x EA = R x
RA).
b) calculating and recording Velocity Ratio =Distance Effort Force Moves
Distance Load Force Moves
c) calculating and recording mechanical advantage (load force / effort force)
d) calculating and recording mechanical efficiency (mechanical
advantage/velocity ratio)
2/ Attach a load of 200 g to the load end of the boom. You might want to
simply use tape to make the attachment.
3/ Position the adjustment pin into the first set of lever advantage adjustment
holes at the effort end of the lever (closest to the end of the boom) once the
hole in the top of the syringe assembly is lined up with the lever advantage
adjustment holes.
4/ Decide on a set distance through which your 200 g mass should move (in
consultation with your teacher and with the rest of your classmates). You and
your classmates should all commit to holding this variable (distance the 200 g
mass moves) constant throughout your testing procedure.
5/ Move the 200 g mass the required distance (outlined in step 4, above).
Then fill in the appropriate part of your table or data chart with the required
information.
6/ Repeat step 5 a total of 5 times, moving the top of the syringe assembly
and the adjustment pin in line with the next closest set of lever advantage
adjustment holes each time.
BLM 8.1 Shovel Arm Assembly
Note: These assembly plans based on a 50 cm long boom and a
24 cm long shovel arm. These lengths can vary.
Cm
5cm
Syringe/
Shovel Arm
Attachment
Drill 13/64” or
7/32” holes for
If gap is too tight
(when plunger end is
positioned with
dowel, above), insert
piece of popsicle
Cm
Cm
BLM 8.2 Boom Extension Design
2cm
Extension Boom Side View
Extension Boom Top View
BLM 8.3 Case Study: Creating, Constructing, and Presenting
a Mechanical Toy Device
The president of "Smooth Move Toy Company" has approached a select group of
her most trusted and experienced employees to design, construct, test, and
market a new mechanical toy. You and other selected classmates (by the
teacher) will form that team of employees who will attempt to successfully meet
the challenge presented to you by your company president.
As one of these select employees, you must create a technical drawing for your
proposed mechanical toy device, remembering to incorporate the following
criteria:
1/ The device must be no more than 30 cm in height.
2/ The device must raise a 200 g mass at least 15 cm in a vertical (straight up)
direction and at least 15 cm in a horizontal (forward, backward, to the left, or to
the right) direction (after raising it up).
3/ The device must use hydraulic or pneumatic power for any of its movement.
4/ The device must incorporate the use of one or more levers.
5/ Pulleys can be incorporated into your device, but use of these is optional.
6/ The device must be as mechanically efficient as possible. Consider ways to
reduce frictional forces that are acting on your device.
7/ Technical drawings (similar in format to those supplied to you for subtask 7)
must be completed for your device. Remember to include an appropriate title,
labels for the various parts of the device, measurements in cm, use of a ruler to
draw straight lines, and a materials list.
You will then present your finished technical drawing to your team members.
Next, you must work as a team to identify the strengths and weaknesses of
each member’s drawing. Remember to use a very positive approach to offering
constructive criticism! The team will then come up with a group design that
“captures the best” of each individual’s design.
The team must then decide, by way of consensus, what materials (and
respective quantities) are needed for construction purposes. The materials that
are available will be reviewed with you by your teacher.
Your team then begins construction, with each group member involved in it.
Once construction is complete, the device needs to be tested to see if it can
meet the criteria set out in # 2, above. Modifications may be necessary.
Use of your learning log is important as part of this design process. In your
learning log reflect on and write answers to the following questions:
a) What have been all of my contributions to the design and construction of this
mechanical toy device?
b) How well has my team worked together (consider strengths and
weaknesses)?
b) Does my team’s mechanical toy device meet all of the given critieria? Does
this newly developed toy device operate efficiently? What supports its efficient
operation? How do you know?
c) What are the most important “selling features” of this product (recall some of
the work that you completed for subtask 2)?
d) How could your team's mechanical toy be improved to make it more
mechanically efficient and, possibly, more appealing to the consumer?
e) In what ways is this type of pneumatic or hydraulic power application used to
meet many of the real, every day needs of people?
You and your teammates will now be required to prepare a presentation of your
finished product for the president (e.g., your teacher) and the rest of the
company executives. Based on your reflections in your learning log, discuss
with your teammates the most important “selling features” of your product.
Each member of your team should be prepared to share some aspect of your
device that will help to ensure that your product is accepted by company
executives.
Timeline:
1/ Personally developed technical drawings to be completed by
_____________________________.
2/ Team Design to be completed by _____________________________.
3/ Construction of mechanical toy device to be completed by
_____________________________.
4/ Reflections in learning log to be completed by _________________________.
5/ Date of my team’s presentation: _______________________________.
Several in-class work periods will be supplied over the next two weeks to
complete all of the steps outlined in the timeline, above.
Rubric 2b for Presentation
for use with Subtask 2 : Let's Sell It!
from the Grade 8 Unit: Structures and Mechanisms
Student Name:
Date:
Expectations for this Subtask to Assess with this Rubric:
8e2
8s89
• use writing for various purposes and in a range of contexts, including school work (e.g., to write technical instructions, to clarify personal concerns, to explore social
issues, to develop imaginative abilities);
• demonstrate understanding of the factors that can affect the manufacturing of a product, including the needs of the consumer.
8 s 1 0 3 – communicate the procedures and results of investigations for specific purposes and to specific audiences, using media works, written notes and descriptions,
charts, graphs, drawings, and oral presentations (e.g., make a display in which they compare the ways in which a closed pneumatic system and a hydraulic system
the
same
of cylinder);
8 s 1 0 8 operate
– analyse
the
use size
of symmetry
in the ergonomic design of objects and systems (e.g., office furniture, computer equipment);
8 s 1 1 4 – evaluate product manuals or help screens (e.g., a manual for a video recorder), focusing on clarity, thoroughness, and general “user-friendliness”, and identify ways
of making the product easier to use;
Category/Criteria
Level 1
Level 2
Level 3
Preparation/Organization - presentation showed limited - presentation showed some
Level 4
organization
- student demonstrated
limited preparation
- presentation was
organization
organized, logical, and
- student demonstrated some interesting
preparation
- student demonstrated
adequate preparation
- presentation was very
well-organized, logical,
interesting, and lively
- student demonstrated a
great deal of preparation
Communication/
Presentation
- voice low unclear and
monotonous
- minimal engagement of
audience via eye contact,
voice, actions, involvement
- voice sometimes low, some
words unclear and somewhat
varied
- some effort to engage
audience
- voice loud enough to be heard easily
and most words clear
- voice was often varied
- spoke at a good pace
- considerable success at engaging
audience
- voice loud enough to be heard easily
and all words clear
- voice consistently varied
- spoke at an excellent pace
- engaged audience by thoroughly
integrating into presentation
Content
- small amount of material
presented is related to topic
- details are random,
inappropriate, or barely
apparent
- some material presented is
not related to topic
- details lack elaboration or
are repetitious
- almost all material
presented is related to topic
- details are elaborate and
appropriate
- all material presented is
related to topic
- details are effective, vivid,
explicit, and/or pertinent
Report Format
- minimal evidence of use of
specified format (e.g.,
paragraphs or charts)
- some evidence of use of
specified format (e.g.,
paragraphs or charts)
- clear evidence of use of
specified format, in an
accurate manner (e.g.,
paragraphs or charts)
- consistent and clear evidence of use of
specified format, in a manner that
enhances the overall "flow" and
understanding of the material (e.g.,
paragraphs or charts)
Knowledge of Topic
- demonstrated limited
understanding of topic
- showed significant
misconceptions
- demonstrated some
understanding of topic
- showed minor
misconceptions
- demonstrated a good
understanding of the topic
- showed no significant
misconceptions
- demonstrated a very strong
understanding of the topic
- showed no misconceptions
Written using the Ontario Curriculum Unit Planner 2.51 PLNR_01 March, 2001* Open Printed on Sep 08, 2001 at 2:17:22 AM Page E-1
Rubric 3 for Syringe System Investigation
for use with Subtask 3 : When Push Comes to Shove
from the Grade 8 Unit: Structures and Mechanisms
Student Name:
Date:
Expectations for this Subtask to Assess with this Rubric:
8s90
– explain how forces are transferred in all directions in fluids (Pascal’s law);
8s93
– compare the effect of pressure on a liquid (e.g., on water in a syringe) with the effect of pressure on a gas (e.g., on air in a syringe);
8 s 1 0 1 – use appropriate vocabulary, including correct science and technology terminology, to communicate ideas, procedures, and results (e.g., use such technical terms
as velocity, velocity ratio, and efficiency);
8 s 1 0 2 – compile qualitative and quantitative data gathered through investigation in order to record and present results, using diagrams, flow charts, frequency tables,
graphs, and stem-and-leaf plots produced by hand or with a computer (e.g., produce and analyse a quotation to complete a job in the home);
8 s 1 0 3 – communicate the procedures and results of investigations for specific purposes and to specific audiences, using media works, written notes and descriptions,
charts, graphs, drawings, and oral presentations (e.g., make a display in which they compare the ways in which a closed pneumatic system and a hydraulic system
operate the same size of cylinder);
Category/Criteria
Level 1
Level 2
Level 3
Level 4
Carrying out the Plan
-instructions followed
-safety
-conducting
-demonstrated a limited understanding
of the instructions
-required substantial assistance in
approaching and carrying out the task
-required continual direction for the use
of materials and equipment
appropriately
-demonstrated a partial understanding of
the instructions
-required some assistance in
approaching and carrying out the task
-required some direction for use of
materials and equipment appropriately
-demonstrated understanding of the
instructions
- with very limited assistance
approached and carried out the task
-required very limited direction for the
use of materials and equipment
appropriately
-demonstrated a thorough understanding
of the instructions
-confidently approached and carried out
the task independently
-used materials and equipment
appropriately without any direction
Recording
-diagrams
-observations
-organization
-diagrams were insufficiently
completed and not labelled
completely
-observations are unorganized
and unclear
-diagrams were sufficiently
labelled and drawn
-observations are adequately
recorded in a somewhat
organized manner and
demonstrate some accuracy of
information
-diagrams were clearly drawn
and appropriately labelled
-observations are sequentially
recorded, easy to read, and
demonstrate accuracy of
information
-diagrams were drawn to scale
and labelled clearly
-observations are excellently
recorded, well-written, and
demonstrate insightfulness and
good detail
Communication of
Understanding
-terminology
-clarity
-explanations were unclear,
uncertainty of the effects of
pressure was shown
-terminology used demonstrated
uncertainty
-explanations demonstrated
some understanding of effects
of pressure
-used some appropriate
terminology in the explanations
-explanations demonstrated
-explanations demonstrated
understanding of effects of
clear understanding of effects of
pressure
pressure
-used appropriate terminology for -used appropriate terminology for
most of the explanations
all of the explanations
Connecting/Relating
Investigation to the
World Around Us
-showed limited understanding
-showed some understanding
-showed an understanding about
about the uses, advantages,
about the uses, advantages,
the uses, advantages, and
disadvantages, and efficiency of disadvantages, and efficiency of efficiency of pneumatics and
pneumatics and hydraulics
pneumatics and hydraulics
hydraulics
-confidently showed
understanding about the uses,
advantages, and efficiency of
pneumatics and hydraulics
Written using the Ontario Curriculum Unit Planner 2.51 PLNR_01 March, 2001* Open Printed on Sep 08, 2001 at 2:17:40 AM Page E-2
Rubric 4 for Investigation of Friction
for use with Subtask 4 : Slow Down
from the Grade 8 Unit: Structures and Mechanisms
Student Name:
Date:
Expectations for this Subtask to Assess with this Rubric:
8s95
– investigate and measure forces that affect the movement of an object (e.g., friction);
8 s 1 0 1 – use appropriate vocabulary, including correct science and technology terminology, to communicate ideas, procedures, and results (e.g., use such technical terms
as velocity, velocity ratio, and efficiency);
8 s 1 0 2 – compile qualitative and quantitative data gathered through investigation in order to record and present results, using diagrams, flow charts, frequency tables,
graphs, and stem-and-leaf plots produced by hand or with a computer (e.g., produce and analyse a quotation to complete a job in the home);
8 s 1 0 3 – communicate the procedures and results of investigations for specific purposes and to specific audiences, using media works, written notes and descriptions,
charts, graphs, drawings, and oral presentations (e.g., make a display in which they compare the ways in which a closed pneumatic system and a hydraulic system
operate the same size of cylinder);
Category/Criteria
Level 1
Level 2
Level 3
Level 4
Carrying out the Plan
-instructions followed
-safety
-conducting
-demonstrated a limited understanding
of the instructions
-required substantial assistance in
approaching and carrying out the task
-required continual direction for the use
of materials and equipment
appropriately and safely
-demonstrated a partial understanding of
the instructions
-required some assistance in
approaching and carrying out the task
-required some direction for use of
materials and equipment appropriately
and safely
-demonstrated understanding of the
instructions
- with very limited assistance
approached and carried out the task
-required very limited direction for the
use of materials and equipment
appropriately and safely
-demonstrated a thorough understanding
of the instructions
-confidently approached and carried out
the task independently
-used materials and equipment
appropriately without any direction and
safely
Recording
-observations
-organization
-made few observations
-observations are unorganized
and unclear
-made observations but they
were insufficient to generate
data
-observations are adequately
recorded in a somewhat
organized manner and
demonstrate some accuracy of
information
-made sufficient observations to
generate data
-observations are sequentially
recorded, easy to read, and
demonstrate accuracy of
information
-made insightful observations
-observations are excellently
recorded, well-written, and
demonstrate good detail
Communication of
Understanding
-terminology
-clarity
-explanations were unclear,
uncertainty of the effects of
friction
-terminology used demonstrated
uncertainty
-explanations demonstrated
some understanding of effects
of friction
-used some appropriate
terminology in the explanations
-explanations demonstrated
-explanations demonstrated
understanding of effects of
clear understanding of effects of
friction
friction
-used appropriate terminology for -used appropriate terminology for
most of the explanations
all of the explanations
Connecting/Relating
Investigation to the
World Around Us
-showed limited understanding
-showed some understanding
-showed an understanding about
about the impact of friction on
about the impact of friction on
the impact of friction on
movement in the world outside of movement in the world outside of movement in the world outside of
the school
the school
the school
-confidently showed
understanding about the impact
of friction on movement in the
world outside of the school
Written using the Ontario Curriculum Unit Planner 2.51 PLNR_01 March, 2001* Open Printed on Sep 08, 2001 at 2:17:40 AM Page E-3
Rubric 5 for Velocity Ratio Investigations
Student Name:
Date:
for use with Subtask 5 : Speed, Distance, Force ... Velocity ... Velocity Ratio
from the Grade 8 Unit: Structures and Mechanisms
Expectations for this Subtask to Assess with this Rubric:
8s96
– distinguish between velocity and speed (i.e., define velocity as speed in a given direction);
8s97
– determine the velocity ratio of devices with pulleys and gears (i.e., divide the distance that a load moves by the distance covered by the force (effort) required to
move it);
8 s 1 0 1 – use appropriate vocabulary, including correct science and technology terminology, to communicate ideas, procedures, and results (e.g., use such technical terms
as velocity, velocity ratio, and efficiency);
8 s 1 0 2 – compile qualitative and quantitative data gathered through investigation in order to record and present results, using diagrams, flow charts, frequency tables,
graphs, and stem-and-leaf plots produced by hand or with a computer (e.g., produce and analyse a quotation to complete a job in the home);
Category/Criteria
Level 1
Level 2
Level 3
Level 4
Carrying out the plan
-instructions followed
-safety
-conducting
-demonstrated a limited understanding
of the instructions
-required substantial assistance in
approaching and carrying out the task
-required continual direction for the use
of materials and equipment
appropriately and safely
-demonstrated a partial understanding of
the instructions
-required some assistance in
approaching and carrying out the task
-required some direction for use of
materials and equipment appropriately
and safely
-demonstrated understanding of the
instructions
- with very limited assistance
approached and carried out the task
-required very limited direction for the
use of materials and equipment
appropriately and safely
-demonstrated a thorough understanding
of the instructions
-confidently approached and carried out
the task independently
-used materials and equipment
appropriately without any direction and
safely
Recording
-tables
-observations
-organization
-tables were insufficiently
completed and not labelled
completely
-observations are unorganized
and unclear
-tables were sufficiently labelled
and design with some accuracy
-observations are adequately
recorded in a somewhat
organized manner and
demonstrate some accuracy of
information
-tables were clearly designed
and appropriately labelled
-observations are sequentially
recorded, easy to read, and
demonstrate accuracy of
information
-tables were designed with great
precision and labelled clearly
-observations are excellently
recorded, well-written, and
demonstrate insightfulness and
good detail
Understanding
Concepts
-clarity
-terminology
-explanations/written work were
unclear, uncertain of the
meaning of velocity and velocity
ratio
-terminology used demonstrated
uncertainty
-explanations/written work
demonstrated some
understanding of velocity and
velocity ratio
-used some appropriate
terminology as part of
explanations
-explanations/written work
demonstrated understanding of
velocity and velocity ratio
-used appropriate terminology for
most of the explanations
-explanations/written work
demonstrated clear
understanding of velocity and
velocity ratio
-used appropriate terminology for
all of the explanations
Written using the Ontario Curriculum Unit Planner 2.51 PLNR_01 March, 2001* Open Printed on Sep 08, 2001 at 2:17:40 AM Page E-4
Rubric 6 for MA/ME Investigations
for use with Subtask 6 : How Efficient Is It?
from the Grade 8 Unit: Structures and Mechanisms
Student Name:
Date:
Expectations for this Subtask to Assess with this Rubric:
8s98
– predict the mechanical efficiency of using different mechanical systems (e.g., a winch).
8 s 1 0 1 – use appropriate vocabulary, including correct science and technology terminology, to communicate ideas, procedures, and results (e.g., use such technical terms
as velocity, velocity ratio, and efficiency);
8 s 1 0 2 – compile qualitative and quantitative data gathered through investigation in order to record and present results, using diagrams, flow charts, frequency tables,
graphs, and stem-and-leaf plots produced by hand or with a computer (e.g., produce and analyse a quotation to complete a job in the home);
Category/Criteria
Level 1
Level 2
Level 3
Level 4
Carrying out the plan
-instructions followed
-safety
-conducting
-demonstrated a limited understanding
of the instructions
-required substantial assistance in
approaching and carrying out the task
-required continual direction for the use
of materials and equipment
appropriately and safely
-demonstrated a partial understanding of
the instructions
-required some assistance in
approaching and carrying out the task
-required some direction for use of
materials and equipment appropriately
and safely
-demonstrated understanding of the
instructions
- with very limited assistance
approached and carried out the task
-required very limited direction for the
use of materials and equipment
appropriately and safely
-demonstrated a thorough understanding
of the instructions
-confidently approached and carried out
the task independently
-used materials and equipment
appropriately without any direction and
safely
Recording
-tables
-observations
-organization
-tables were insufficiently
completed and not labelled
completely
-observations are unorganized
and unclear
-tables were sufficiently labelled
and design with some accuracy
-observations are adequately
recorded in a somewhat
organized manner and
demonstrate some accuracy of
information
-tables were clearly designed
and appropriately labelled
-observations are sequentially
recorded, easy to read, and
demonstrate accuracy of
information
-tables were designed with great
precision and labelled clearly
-observations are excellently
recorded, well-written, and
demonstrate insightfulness and
good detail
Understanding
Concepts
-clarity
-terminology
-explanations/written work were
unclear, uncertain of the
meaning of mechanical
advantage and mechanical
efficiency
-terminology used demonstrated
uncertainty
-explanations/written work
demonstrated some understanding of
mechanical advantage and mechanical
efficiency
-used some appropriate terminology as
part of explanations
-explanations/written work
demonstrated understanding of
mechanical advantage and
mechanical efficiency
-used appropriate terminology for
most of the explanations
-explanations/written work
demonstrated clear
understanding of mechanical
advantage and mechanical
efficiency
-used appropriate terminology for
all of the explanations
Written using the Ontario Curriculum Unit Planner 2.51 PLNR_01 March, 2001* Open Printed on Sep 08, 2001 at 2:17:40 AM Page E-5
Rubric 7 for Hydraulic Test Lever Activity
for use with Subtask 7 : Linking The Systems
from the Grade 8 Unit: Structures and Mechanisms
Student Name:
Date:
Expectations for this Subtask to Assess with this Rubric:
8s98
– predict the mechanical efficiency of using different mechanical systems (e.g., a winch).
8 s 1 0 1 – use appropriate vocabulary, including correct science and technology terminology, to communicate ideas, procedures, and results (e.g., use such technical terms
as velocity, velocity ratio, and efficiency);
8 s 1 0 2 – compile qualitative and quantitative data gathered through investigation in order to record and present results, using diagrams, flow charts, frequency tables,
graphs, and stem-and-leaf plots produced by hand or with a computer (e.g., produce and analyse a quotation to complete a job in the home);
Category/Criteria
Level 1
Level 2
Level 3
Level 4
Understanding of
Concepts
(e.g., stability, force,
pressure, mechanical
advantage)
- showed understanding of
few of the basic concepts
- gave explanations showing
limited understanding of the
concept
- showed understanding of
some of the basic concepts
- gave partial explanations
- showed understanding of
most of the basic concepts
- usually gave complete or
nearly complete explanations
- showed understanding of
all of the basic concepts
- always gave complete
explanations
Design Skills
(e.g., following design
plans, using appropriate
tools, materials, and
strategies)
- could not follow design
plans without significant
assistance
- using tools and materials
that required assistance
- followed the design plans
with limited assistance
- used tools and materials
successfully with some
assistance
- followed the design plans
independently and with
accuracy
- used tools and materials in
ways that reflected good
strategy development
- followed the design plans
independently, with great
attention to detail, and/or made
suggestions for improvements
- used tools and materials in
ways that reflected excellent
strategy development
Data Collection Through
Investigation
(e.g., qualitative and
quantitative data related
to mechanical efficiency
of hydraulic lever)
- completed investigation with
significant assistance
- table or chart was provided
- data collection was
incomplete or done with
significant assistance
- completed investigation with
some assistance
- table or chart was created
with some assistance
- completed investigation with
occasional assistance
- table or chart was created
independently and correctly
Communication of
Understanding
(e.g., how levers and
hydraulics affect
mechanical efficiency)
- communicated with little
clarity and precision
- rarely used appropriate
science and technology
terminology
- communicated with some
clarity and precision
- sometimes used
appropriate science and
technology terminology
- generally communicated
with clarity and precision
- usually used appropriate
science and technology
terminology
- data collection was complete/
almost complete with formulae
use being fairly accurate
- completed investigation
independently
- table or chart was completely
self-designed and accurate
- data collection was complete
- data collection was complete
with formulae use being accurate with formulae use demonstrating
thorough understanding of data
- consistently communicated
with clarity and precision
- consistently used
appropriate science and
technology terminology
Written using the Ontario Curriculum Unit Planner 2.51 PLNR_01 March, 2001* Open Printed on Sep 08, 2001 at 2:17:40 AM Page E-6
Rubric 8 for Evaluating Culminating Activity
for use with Subtask 8 : Toying With Efficiency
from the Grade 8 Unit: Structures and Mechanisms
Student Name:
Date:
Expectations for this Subtask to Assess with this Rubric:
8s89
• demonstrate understanding of the factors that can affect the manufacturing of a product, including the needs of the consumer.
8 s 1 0 4 – design and make a mechanical system that is operated by hydraulic or pneumatic power;
8 s 1 0 5 – select and use appropriate materials and strategies to make a product;
8 s 1 0 6 – produce technical drawings and layout diagrams of a structure or a mechanical system that they are designing, using a variety of resources.
8 s 1 1 8 – evaluate their own designs against the original need, and propose modifications to improve the quality of the products.
Category/Criteria
Level 1
Level 2
Level 3
Level 4
Development of
Technical Plan
- clarity
- use of given criteria
- developed a plan that is
unclear and incomplete
- took into account little or none
of the given criteria
- developed a plan that is limited
in how appropriate, clear, and
complete it is
- identified some of the given
criteria
- developed a plan that is
appropriate, clear, and complete
- identified most, if not all, of the
given criteria
- developed a reproducible plan
that is appropriate, efficient,
clear, and complete
- identified all of the given
criteria
Carrying Out of the Plan
- use of tools and other
materials
-safety
- performance of model
- incorporation of safety criteria
- used tools, equipment, and materials
with limited accuracy, and limited respect
for safe practices and only with
assistance
- performance of model did not
demonstrate the required function
- incorporated few elements of the original
plan
- addressed very little of the given criteria
in the construction
- selected and used tools, equipment, and
materials adequately, safely and with
some assistance
- performance of model demonstrated the
required function in a limited way
- incorporated some elements of the
original plan
- addressed some of the given criteria in
the construction
- selected and used tools, equipment, and
materials effectively, safely and with only
occasional assistance
- performance of model demonstrated the
required function within acceptable limits
- incorporated most, if not all, elements of
the original plan
- addressed most, if not all, of the given
criteria in the construction
- selected and used tools, equipment, and
materials safely in innovative ways and
with little or no assistance
- performance of model demonstrated the
required function, exceeding expected
level
- incorporated all elements of the original
plan and made any necessary
modifications during construction
- addressed exact specifications of the
given criteria in the construction
Quality of Explanations
- communicated her/his understanding of
planning and construction, and “strengths”
of the finished product, with limited clarity
and precision
- explanation of device's mechanical
efficiency was completely inaccurate
- rarely used appropriate terminology
- communicated her/his understanding of
planning and construction, and “strengths”
of the finished product, with some clarity
and precision
- explanation of device's mechanical
efficiency, although inaccurate, showed a
limited understanding of its
importance/value
- sometimes used appropriate terminology
- generally communicated her/his
understanding of planning and
construction, and “strengths” of the
finished product, with clarity and
precision
- explanation of device's mechanical
efficiency was accurate or very close,
showing some understanding of its
importance/value
- usually used appropriate terminology
- consistently communicated her/his
understanding of planning and
construction, and “strengths” of the
finished product, with clarity and
precision
- explanation of device's mechanical
efficiency was accurate, showing a strong
understanding of its importance/value
- consistently used appropriate
terminology
Connecting Science and
Technology and the World
Outside the School
- showed little understanding of the
following: the value of working as a
member of a team, basic marketing
strengths of the product (as these
reflected real world working strategies),
ways of improving mechanical efficiency,
identifying real life applications of
hydraulics/pneumatics
- showed some understanding of the
following: the value of working as a
member of a team, basic marketing
strengths of the product (as these
reflected real world working strategies),
ways of improving mechanical efficiency,
identifying real life applications of
hydraulics/pneumatics
- showed an understanding of the
following: the value of working as a
member of a team, basic marketing
strengths of the product (as these
reflected real world working strategies),
ways of improving mechanical efficiency,
identifying real life applications of
hydraulics/pneumatics
- demonstrated some leadership skills as
a “company employee”
- showed an understanding of the
following: the value of working as a
member of a team, basic marketing
strengths of the product (as these
reflected real world working strategies),
ways of improving mechanical efficiency,
identifying real life applications of
hydraulics/pneumatics, as well as their
implications
- demonstrated leadership skills as a
“company employee”
- planning, construction, finished
product
- mechanical efficiency
- terminology
Written using the Ontario Curriculum Unit Planner 2.51 PLNR_01 March, 2001* Open Printed on Sep 08, 2001 at 2:17:40 AM Page E-7
Rubric 1 for Gaining Leverage
for use with Subtask 1 : Gaining Leverage
from the Grade 8 Unit: Structures and Mechanisms
Student Name:
Date:
Expectationsfor this Subtask to Assess with this Rubric:
8s87
• demonstrate an understanding of the factors that contribute to the efficient operation of mechanisms and systems;
8 s 1 0 1 – use appropriate vocabulary, including correct science and technology terminology, to communicate ideas, procedures, and results (e.g., use such technical terms
as velocity, velocity ratio, and efficiency);
8 s 1 0 3 – communicate the procedures and results of investigations for specific purposes and to specific audiences, using media works, written notes and descriptions,
charts, graphs, drawings, and oral presentations (e.g., make a display in which they compare the ways in which a closed pneumatic system and a hydraulic system
operate the same size of cylinder);
Category/Criteria
Level 1
Level 2
– communicated with little
clarity and precision
– rarely used appropriate
science and technology
-using terms: load, force,
and units of
input, output, fulcrum, lever, terminology
measurement
Communication of
Required Knowledge
force, etc.
Level 3
Level 4
– communicated with some
clarity and precision
– sometimes used
appropriate science and
technology terminology and
units of measurement
– generally communicated
with clarity and precision
– usually used appropriate
science and technology
terminology and units of
measurement
– consistently communicated
with clarity and precision
– consistently used
appropriate science and
technology terminology and
units of measurement
Understanding of Basic
Concepts
– showed understanding of few
of the basic concepts
– demonstrated significant
misconception
– gave explanations showing
limited understanding of the
concepts related to lever
classes
– identify and explain lever
classes
– showed understanding of
some of the basic concepts
– demonstrated minor
misconceptions
– gave partial explanations
related to lever classes
– showed understanding of
most of the basic concepts
– demonstrated no
significant misconceptions
– usually gave complete or
nearly complete explanations
related to lever classes
– showed understanding of
all of the basic concepts
– demonstrated no
misconceptions
– always gave complete
explanations related to lever
classes
Relating of Science and
Technology to Each
Other and to the World
Outside the School
– showed little understanding of
connections between science
and technology in familiar
contexts
– showed little understanding of
connections between science
and technology and the world
outside the school
– showed some understanding
of connections between science
and technology in familiar
contexts
– showed some understanding
of connections between science
and technology and the world
outside the school
– showed understanding of
connections between science
and technology in familiar
contexts
– showed understanding of
connections between science
and technology and the world
outside the school
– showed understanding of
connections between science
and technology in both familiar
and unfamiliar contexts
– showed understanding of
connections between science
and technology and the world
outside the school, as well as
their implications
-classifies examples
according to lever classes
Written using the Ontario Curriculum Unit Planner 2.51 PLNR_01 March, 2001* Open Printed on Sep 08, 2001 at 2:17:54 AM Page E-8
Rubric 2a for Communication
for use with Subtask 2 : Let's Sell It!
from the Grade 8 Unit: Structures and Mechanisms
Student Name:
Date:
Expectationsfor this Subtask to Assess with this Rubric:
8e46
• provide clear answers to questions and well-constructed explanations or instructions in classroom work;
8e49
• express and respond to a range of ideas and opinions concisely, clearly, and appropriately;
8s89
• demonstrate understanding of the factors that can affect the manufacturing of a product, including the needs of the consumer.
8 s 1 1 0 – identify the kinds of information that assist consumers in making a decision about buying a product (e.g., information on performance, durability, safety, benefits to
health);
8 s 1 1 6 – explain the economic, social, and environmental factors that can determine whether a product is manufactured (e.g., costs of materials and equipment, availability of
skilled labour, potential harmfulness of the product);
Category/Criteria
Level 1
Level 2
Level 3
Level 4
- explanations are
incomplete, contain little
detail, and/or are inaccurate
- explanations are fairly
complete, contain some
detail, and offer inconsistent
accuracy
- explanations are generally
complete, detailed and
accurate
- explanations demonstrate
insight, significant detail, and
are always accurate
- explanations include limited
support to justify conclusions
- explanations include some
support to justify conclusions
- explanations include
adequate support to justify
conclusions
- explanations include strong
support to justify conclusions
Reflection/Openness to
Change in Thinking in
Written and Oral
Communication
- identifies a few sources of
error
- identifies and explains, in a
limited way, a few sources of
error
- identifies and explains
several sources of error
- identifies and explains
all/almost all sources of error
- corrections are attempted
with some accuracy
- corrections are generally
made with accuracy
- corrections are consistently
made with accuracy
Relating Science and
Technology to World
Outside School
- uses limited gradeappropriate Science and
Technology concepts
- uses some gradeappropriate Science and
Technology criteria/concepts
- uses grade-appropriate
Science and Technology
criteria/concepts
- knows grade-appropriate
Science and Technology
terminology and uses this
knowledge to demonstrate a
thorough understanding of
the topic
Quality of Explanations
- corrections are attempted
with limited accuracy
Written using the Ontario Curriculum Unit Planner 2.51 PLNR_01 March, 2001* Open Printed on Sep 08, 2001 at 2:17:54 AM Page E-9
Expectation List
Structures and Mechanisms
Page 1
Mechanical Efficiency An Integrated Unit for Grade 8
Selected
Assessed
English Language--8e1
• communicate ideas and information for a variety of purposes (to evaluate information, to compare points of view) and to
specific audiences, using forms appropriate for their purpose (e.g., a survey soliciting opinions on an environmental issue)
and features appropriate to the form (e.g., focused questions);
• use writing for various purposes and in a range of contexts, including school work (e.g., to write technical instructions, to
clarify personal concerns, to explore social issues, to develop imaginative abilities);
8e2
1
1
English Language---Oral and Visual Communication
8e46
8e47
8e49
• provide clear answers to questions and well-constructed explanations or instructions in classroom work;
• listen attentively to organize and classify information and to clarify thinking;
• express and respond to a range of ideas and opinions concisely, clearly, and appropriately;
2
2
1
1
1
1
1
Mathematics---Measurement
8m35
8m36
• demonstrate a verbal and written understanding of and ability to apply accurate measurement and estimation strategies that
relate to their environment;
• identify relationships between and among measurement concepts (linear, square, cubic, temporal, monetary);
2
Mathematics---Patterning and Algebra
8m77
• identify, create, and solve simple algebraic equations;
1
Mathematics---Data Management and Probability
8m91
8m93
8m94
• systematically collect, organize, and analyse primary data;
• interpret displays of data and present the information using mathematical terms;
• evaluate data and draw conclusions from the analysis of data;
2
1
1
Science and Technology---Structures and Mechanisms
8s87
8s88
8s89
8s90
8s91
8s93
8s94
8s95
8s96
8s97
8s98
8s99
8s100
8s101
8s102
8s103
8s104
8s105
8s106
• demonstrate an understanding of the factors that contribute to the efficient operation of mechanisms and systems;
• design and make systems of structures and mechanisms, and investigate the efficiency of the mechanical devices within
them;
• demonstrate understanding of the factors that can affect the manufacturing of a product, including the needs of the consumer.
– explain how forces are transferred in all directions in fluids (Pascal’s law);
– describe in quantitative terms the relationship between force, area, and pressure;
– compare the effect of pressure on a liquid (e.g., on water in a syringe) with the effect of pressure on a gas (e.g., on air in a
syringe);
– explain, using their observations, how the use of appropriate levers and ways of linking the components of fluid systems can
improve the performance of the systems (e.g., systems in a steam shovel, in a robot);
– investigate and measure forces that affect the movement of an object (e.g., friction);
– distinguish between velocity and speed (i.e., define velocity as speed in a given direction);
– determine the velocity ratio of devices with pulleys and gears (i.e., divide the distance that a load moves by the distance
covered by the force (effort) required to move it);
– predict the mechanical efficiency of using different mechanical systems (e.g., a winch).
– formulate questions about and identify needs and problems related to the efficient operation of mechanical systems, and
explore possible answers and solutions (e.g., test a device at each stage of its development and evaluate its performance in
relation to specific criteria);
– plan investigations for some of these answers and solutions, identifying variables that need to be held constant to ensure a fair
test and identifying criteria for assessing solutions;
– use appropriate vocabulary, including correct science and technology terminology, to communicate ideas, procedures, and
results (e.g., use such technical terms as velocity, velocity ratio, and efficiency);
– compile qualitative and quantitative data gathered through investigation in order to record and present results, using
diagrams, flow charts, frequency tables, graphs, and stem-and-leaf plots produced by hand or with a computer (e.g.,
produce and analyse a quotation to complete a job in the home);
– communicate the procedures and results of investigations for specific purposes and to specific audiences, using media
works, written notes and descriptions, charts, graphs, drawings, and oral presentations (e.g., make a display in which they
compare the ways in which a closed pneumatic system and a hydraulic system operate the same size of cylinder);
– design and make a mechanical system that is operated by hydraulic or pneumatic power;
– select and use appropriate materials and strategies to make a product;
– produce technical drawings and layout diagrams of a structure or a mechanical system that they are designing, using a
variety of resources.
2
1
1
1
1
1
1
1
2
1
1
1
1
2
2
1
1
7
1
5
1
4
1
1
1
1
1
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Expectation List
Structures and Mechanisms
Page 2
Mechanical Efficiency An Integrated Unit for Grade 8
8s107
8s108
8s110
8s111
8s112
8s113
8s114
8s115
8s116
8s117
8s118
Selected Assessed
– explain how human weight, height, age, sex, and physical capability affect the design of products (e.g., car seats,
1
snowmobiles, zippers);
– analyse the use of symmetry in the ergonomic design of objects and systems (e.g., office furniture, computer equipment);
1
– identify the kinds of information that assist consumers in making a decision about buying a product (e.g., information on
1
performance, durability, safety, benefits to health);
– identify consumer expectations regarding the function and effectiveness of a product, using information collected in a survey
1
1
they made, and recognize that expectations may change;
– recognize the importance of unbiased testing of control samples and independent evaluation of the test results before a
1
product is manufactured;
– identify the personal and societal factors that determine whether a product is used;
1
– evaluate product manuals or help screens (e.g., a manual for a video recorder), focusing on clarity, thoroughness, and
1
general “user-friendliness”, and identify ways of making the product easier to use;
– assess the impact on the environment of the use and disposal of various products (e.g., motor oil, Freon);
1
– explain the economic, social, and environmental factors that can determine whether a product is manufactured (e.g., costs of
1
materials and equipment, availability of skilled labour, potential harmfulness of the product);
– make informed judgements about products designed and made by others;
1
– evaluate their own designs against the original need, and propose modifications to improve the quality of the products.
1
The Arts---Visual Arts
8a25
8a26
• produce two- and three-dimensional works of art that communicate a variety of ideas (thoughts, feelings, experiences) for
specific purposes and to specific audiences, using a variety of art forms;
• define the principles of design (emphasis, balance, rhythm, unity, variety, proportion), and use them in ways appropriate for
this grade when producing and responding to works of art;
1
2
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Expectation Summary
Selected
Structures and Mechanisms
Assessed
Mechanical Efficiency An Integrated Unit for Grade 8
English Language
8e1
8e11
8e21
8e31
8e41
8e51
8e61
1
8e2
8e12
8e22
8e32
8e42
8e52
8e62
1
8e3
8e13
8e23
8e33
8e43
8e53
8e63
8e4
8e14
8e24
8e34
8e44
8e54
8e64
8e5
8e15
8e25
8e35
8e45
8e55
8e65
8e6
8e16
8e26
8e36
8e46
8e56
8e66
8f3
8f13
8f4
8f14
8f5
8f15
8f6
8f16
8m3
8m13
8m23
8m33
8m43
8m53
8m63
8m73
8m83
8m93
8m103
8m113
8m4
8m14
8m24
8m34
8m44
8m54
8m64
8m74
8m84
8m94
8m104
8m114
8m5
8m15
8m25
8m35
8m45
8m55
8m65
8m75
8m85
8m95
8m105
8m115
8m6
8m16
8m26
8m36
8m46
8m56
8m66
8m76
8m86
8m96
8m106
8m116
2
1
8e7
8e17
8e27
8e37
8e47
8e57
8e67
8e8
8e18
8e28
8e38
8e48
8e58
8e9
8e19
8e29
8e39
8e49
8e59
8f7
8f17
8f8
8f9
8f10
8m7
8m17
8m27
8m37
8m47
8m57
8m67
8m77
8m87
8m97
8m107
8m117
8m8
8m18
8m28
8m38
8m48
8m58
8m68
8m78
8m88
8m98
8m108
8m118
8m9
8m19
8m29
8m39
8m49
8m59
8m69
8m79
8m89
8m99
8m109
8m119
8m10
8m20
8m30
8m40
8m50
8m60
8m70
8m80
8m90
8m100
8m110
8m120
8s8
8s18
8s28
8s38
8s48
8s58
8s68
8s78
8s88
8s98
8s108
8s118
8s128
8s138
8s148
8s9
8s19
8s29
8s39
8s49
8s59
8s69
8s79
8s89
8s99
8s109
8s119
8s129
8s139
8s10
8s20
8s30
8s40
8s50
8s60
8s70
8s80
8s90
8s100
8s110
8s120
8s130
8s140
2
1
1
8e10
8e20
8e30
8e40
8e50
8e60
French as a Second Language
8f1
8f11
8f2
8f12
Mathematics
8m1
8m11
8m21
8m31
8m41
8m51
8m61
8m71
8m81
8m91
8m101
8m111
8m121
8m2
8m12
8m22
8m32
8m42
8m52
8m62
8m72
8m82
8m92
8m102
8m112
8m122
2
1
1
1
1
2
1
Science and Technology
8s1
8s11
8s21
8s31
8s41
8s51
8s61
8s71
8s81
8s91
8s101
8s111
8s121
8s131
8s141
1
1
1
7
1
8s2
8s12
8s22
8s32
8s42
8s52
8s62
8s72
8s82
8s92
8s102
8s112
8s122
8s132
8s142
1
1
5
8s3
8s13
8s23
8s33
8s43
8s53
8s63
8s73
8s83
8s93
8s103
8s113
8s123
8s133
8s143
1
1
4
1
8s4
8s14
8s24
8s34
8s44
8s54
8s64
8s74
8s84
8s94
8s104
8s114
8s124
8s134
8s144
2
1
1
1
8s5
8s15
8s25
8s35
8s45
8s55
8s65
8s75
8s85
8s95
8s105
8s115
8s125
8s135
8s145
1
1
1
1
8s6
8s16
8s26
8s36
8s46
8s56
8s66
8s76
8s86
8s96
8s106
8s116
8s126
8s136
8s146
1
1
1
8s7
8s17
8s27
8s37
8s47
8s57
8s67
8s77
8s87
8s97
8s107
8s117
8s127
8s137
8s147
2
1
1
1
1
1
1
2
1
1
1
2
1
History
8h1
8h11
8h21
8h31
8h41
8h51
8h2
8h12
8h22
8h32
8h42
8h52
8h3
8h13
8h23
8h33
8h43
8h53
8h4
8h14
8h24
8h34
8h44
8h54
8h5
8h15
8h25
8h35
8h45
8h55
8h6
8h16
8h26
8h36
8h46
8h56
8h7
8h17
8h27
8h37
8h47
8h57
8h8
8h18
8h28
8h38
8h48
8h9
8h19
8h29
8h39
8h49
8h10
8h20
8h30
8h40
8h50
8g3
8g13
8g23
8g33
8g43
8g53
8g4
8g14
8g24
8g34
8g44
8g54
8g5
8g15
8g25
8g35
8g45
8g55
8g6
8g16
8g26
8g36
8g46
8g56
8g7
8g17
8g27
8g37
8g47
8g57
8g8
8g18
8g28
8g38
8g48
8g9
8g19
8g29
8g39
8g49
8g10
8g20
8g30
8g40
8g50
Geography
8g1
8g11
8g21
8g31
8g41
8g51
8g2
8g12
8g22
8g32
8g42
8g52
Health & Physical Education
8p1
8p11
8p21
8p31
8p41
8p2
8p12
8p22
8p32
8p3
8p13
8p23
8p33
8p4
8p14
8p24
8p34
8p5
8p15
8p25
8p35
8p6
8p16
8p26
8p36
8p7
8p17
8p27
8p37
8p8
8p18
8p28
8p38
8p9
8p19
8p29
8p39
8p10
8p20
8p30
8p40
8a2
8a12
8a22
8a32
8a42
8a52
8a62
8a3
8a13
8a23
8a33
8a43
8a53
8a63
8a4
8a14
8a24
8a34
8a44
8a54
8a64
8a5
8a15
8a25
8a35
8a45
8a55
8a65
8a6
8a16
8a26
8a36
8a46
8a56
8a66
8a7
8a17
8a27
8a37
8a47
8a57
8a8
8a18
8a28
8a38
8a48
8a58
8a9
8a19
8a29
8a39
8a49
8a59
8a10
8a20
8a30
8a40
8a50
8a60
The Arts
8a1
8a11
8a21
8a31
8a41
8a51
8a61
1
2
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1
1
Unit Analysis
Page 1
Structures and Mechanisms
Mechanical Efficiency An Integrated Unit for Grade 8
Analysis Of Unit Components
8 Subtasks
77 Expectations
137 Resources
86 Strategies & Groupings
-- Unique Expectations -5 Language Expectations
6 Mathematics Expectations
30 Science And Tech Expectations
2 Arts Expectations
Resource Types
9
34
0
3
2
8
43
38
0
0
0
0
Rubrics
Blackline Masters
Licensed Software
Print Resources
Media Resources
Websites
Material Resources
Equipment / Manipulatives
Sample Graphics
Other Resources
Parent / Community
Companion Bookmarks
Groupings
Assessment Recording Devices
5
7
6
3
1
7
Students Working As A Whole Class
Students Working In Small Groups
Students Working Individually
Anecdotal Record
Checklist
Rubric
Teaching / Learning Strategies
Assessment Strategies
3
1
1
3
1
3
4
2
1
1
2
2
1
4
1
1
2
2
1
1
4
2
5
7
2
Brainstorming
Case Study
Classifying
Collaborative/cooperative Learning
Concept Clarification
Discussion
Experimenting
Fair Test
Independent Study
Inquiry
Learning Log/ Journal
Model Making
Note-making
Problem-solving Strategies
Research
Working With Manipulatives
Classroom Presentation
Conference
Essay
Introduction
Learning Log
Observation
Performance Task
Questions And Answers (oral)
Self Assessment
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